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The Christian Philosopher; or, Science and Religion

Natural Philosophy

Natural Philosophy.

Having, in the preceding sketches, considerably exceeded the limits originally prescribed for this department of my subject, I am reluctantly compelled to dispatch the remaining sciences with a few brief artices.

The object of Natural Philosophy is, to observe and describe the phenomena of the material universe, with a view to discover their causes, and the laws by which the Almighty directs the movements of all bodies in heaven and on earth. It embraces an investigation of the laws of gravitation, by which the planets are directed in their motions; the laws by which water, air, light, and heat, are regulated, and the effects they produce in the various states in which they operate; the nature of colors, sounds, electricity, galvanism and magnetism, and the laws of their operation the causes which operate in the production of page 93 thunder, lightning, luminous and fiery meteors, hail, rain, snow, dew, and other atmospherical phenomena. In short, it embraces all the objects of Natural History formerly alluded to, with a view to ascertain the causes of their varied appearances, and the principles that operate in the changes to which they are subject; or, in other words, the laws by which the diversified phenomena of universal nature are produced and regulated. One subordinate use of the knowledge derived from this science, is, to enable us to construct all those mechanical engines which facilitate human labor, and increase the comforts of mankind, and all those instruments which tend to enlarge our views of the operations of nature. A still higher and nobler use to which philosophy is subservient, is to demonstrate the Wisdom and Intelligence of the Great First Cause of all things, and to enlarge our conceptions of the admirable contrivance and design which appear in the different departments of universal nature. In this view, it may be considered as forming a branch of Natural Theology, or, in other words, a branch of the religion of angels, and of all other holy intelligences.

This department of natural science has generally been divided into the following branches:—

I. Mechanics.—This branch, considered in its most extensive range, includes an investigation of the general properties of matter; such as solidity, extension, divisibility, motion, attraction, and repulsion—the law of gravitation, and of central forces, as they appear to operate in the motions of the celestial bodies; and on the surface of our globe, in the phenomena of falling bodies, the motions of projectiles, the vibration of pendulums, etc.,—the theory of machines, the principles on which their energy depends; the properties of the mechanical powers—the lever, the wheel and axle, the pulley, the inclined plane, the wedge, and the screw,—and the effects resulting from their various combinations. From the investigations of philosophers on these subjects, we learn the laws by which the great bodies of the universe are directed in their motions; the laws which bind together the different portions of matter on the surface of the earth, and which regulate the motions of animal, vegetable, and inanimate nature; and the principles on which cranes, mills, wheel-carriages, thrashing-machines, pile-engines, locomotive carriages, and other engines, are constructed; by means of which man has been enabled to accomplish operations far beyond the limits of his own physical powers.

Without a knowledge of the laws of motion, and assistance from the combined effects of the mechanical powers, man would be a very limited being, his enjoyments would be few, and his active energies confined within a very narrow range. In a savage state, ignorant of manufactures, agriculture, architecture, navigation, and the other arts which depend upon mechanical combinations, he is exposed, without shelter, to the inclemencies of the seasons; he is unable to transport himself beyond seas and oceans, to visit other climes, and other tribes of his fellow-men; he exists in the desert, comfortless and unimproved; the fertile soil, over which he roams, is covered with thorns and briers, and thickets, for the naunt of beasts of prey; his enjoyments are little superior to those of the lion, the hyena, and the elephant, while he is much their inferior in point of agility and physical strength. But, when philosophy has once demonstrated the principles of Mechanics, and introduced the practice of the useful Arts, “the wilderness and the solitary place are made glad, and the desert rejoices and blossoms as the rose.” Cities are founded, and gradually rise to opulence and splendor; palaces and temples are reared; the damp cavern, and the rush-built hut, are exchanged for the warm and comfortable apartments of a substantial mansion; ships are built, and navigated across the ocean; the treasures of one country are conveyed to another; an intercourse is carried on between the most distant tribes of mankind; commerce flourishes, and machinery of all kinds is erected for facilitating human labor, and promoting the enjoyments of man. And, when the principles and the practice of “pure and undefiled religion” accompany these physical and mechanical operations, love and affection diffuse their benign influence; the prospect brightens as years roll on, and man advances, with pleasure and improvement, to the scene of his high destination.

II. Hydrostatics treats of the pressure and equilibrium of fluids. From the experiments which have been made in this branch of philosophy, the following important principles, among many others, have been deduced:—

(1.) That the surface of all waters which have a communication while they are at rest, will be perfectly level.—This principle will be more clearly understood by an inspection of the following figures. If water be poured into the tube A (fig. 24), it will run through the horizontal tube E, and rise in the opposite tube B, to the same hight at which it stands at A. It is on this principle that water is now conveyed under ground through conduit pipes, and made to rise to the level of the fountain whence it is drawn. The city of Edinburgh, a considerable part of which is elevated above the level of the surrounding country, is supplied with water from a reservoir on the Pentland hills, several miles distant. The water is conveyed in leaden pipes down the declivity of the hill, along the interjacent plain, and up to the entrance of the castle, whence it is distributed to all parts of the city. If the point A represent the level of the reservoir, C D will represent the plain along which the water is conveyed, and B the elevation to which it rises on the Castle-hill. On the same principle, and in a similar manner, the city of London is supplied with water from water-works at the London bridge. Had the ancients been acquainted with this simple, but important principle, it would have saved them the labor and expense of rearing those stupendous works of art, the Aqueducts, which consisted of numerous arches of vast size, and sometimes piled one above another.

Fig. 24

Fig. 24

Fig. 25 represents the syphon, the action of which depends upon the pressure of the atmo- page 94 sphere. If this instrument be filled with water, or any other liquid, and the shorter leg G plunged to the bottom of a cask, or other vessel containing the same liquid, the water will run out at the longer leg F, until the vessel be emptied, in consequence of the atmospheric pressure upon the surface of the liquid. Oll this principle water may be conveyed over a rising ground to any distance; provided the perpendicular hight of the syphon above the surface of the water in the fountain does not exceed thirty-two or thirty-three feet. On the same principle are constructed the fountain at command, the cup of Tantalus, and other entertaining devices. The same principle, too, enables us to account for springs which are sometimes found on the tops of mountains, and for the phenomena of intermitting springs, or those which flow and stop by regular alternations.

Fig. 25

Fig. 25

The following figure will explain the nature of intermitting springs. Suppose A B a cavity or receptacle of water formed in the bowels of a hill where the spring is situated, which gradually fills with water like other reservoirs, and that by the interposition of some stratum of rock or other substance, the tube C D, which conveys the water to the spring or mouth where it issues—is bent in the form of a syphon; whenever the reservoir A B is filled as high as the bend of the tube, or to the level of h i, the water will rise in the tube, and begin to flow into the spring, which will continue until the reservoir be exhausted. While this process is going on, the water in the spring will rise, and as soon as the reservoir is exhausted, the water will appear to fall in the well of the spring, and will continue to fall until the reservoir is again supplied to the hight of the syphon when the process of filling will be again renewed; It is obvious that unless the water in the reservoir rises above the hight of the bend of the syphon E, the well cannot be filled.

(2.) Any quantity of fluid, however small, may be made to counterpoise any quantity, however large This is what has generally been termed the Hydrostatical Paradox; and from this principle it follows, that a given quantity of water may exert a force several hundred times greater or less, according to the manner in which it is employed. This force depends on the hight of the column of water, independent of its quantity; for its pressure depends on its perpendicular hight. By means of water conveyed through a very small perpendicular tube, of great length, a very strong hogshead has been burst to pieces, and the water scattered about with incredible force. On this principle, the hydrostatic press, and other engines of immense power, have been constructed.

(3.) Every body which is heavier than water, or which sinks in it, displaces so much of the water as is equal to the bulk of the body immersed in the water.—On this principle, the specific gravities, or comparative weight, of all bodies are determined. It appears to have been first ascertained by Archimedes, and by means of it, he determined that the golden crown of the king of Syracuse had been adulterated by the workmen. From this principle we learn, among many other things, the specific gravity of the human body; and that four pounds of cork will preserve a person weighing 135 pounds from sinking, so that he may remain with his head completely above water.

Hydraulics, which has sometimes been treated as a distinct department of mechanical philosophy, may be considered as a branch of Hydrostatics. It teaches us what relates to the motion of fluids, and how to estimate their velocity and force On the principles of this science, all machines worked by water are constructed—as steam-engines, water-mills, common and forcing pumps, syphons, fountains, and fire-engines.

Fig. 26

Fig. 26

III. Pneumatics.—This branch of philosophy treats of the nature and properties of the atmosphere, and of their effects on solid and fluid bodies. From this science we learn that air has weight, and presses on all sides like other fluids; that the pressure of the atmosphere upon the top of a mountain is less than on the plain beneath; that it presses upon our bodies with the weight of several thousand pounds more at one time than at another; that air can be compressed into forty thousand times less space than it naturally occupies; that it is of an elastic or expansive nature, and that the force of its spring is equal to its weight; that its elasticity is increased by heat; that it is necessary to the production of sound, the support of flame and animal life, and the germination and growth of all kinds of vegetables.

These positions are proved and illustrated by such experiments as the following:—The general pressure of the atmosphere is proved by such experiments as those detailed in Note II of the Appendix. The following experiment proves that air is compressible. If a glass tube, open at one end, and close at the other, be plunged, with the open end downward, into a tumbler of water, the water will rise a little way in the tube; which shows, that the air which filled the tube is compressed by the water into a smaller space. The elasticity of air is proved by tying up a bladder, with a very small quantity of air within it page 95 and putting it under the receiver of an air-pump, when it will be seen gradually to inflate, until it becomes of its full size. A similar effect would take place, by carrying the bladder to the higher regions of the atmosphere. On the compression and elasticity of the air, depends the construction of that dangerous and destructive instrument, the Air-gun. That it is capable of being rarefied by heat, is proved by holding to the fire a half-blown bladder, slightly tied at the neck, when it will dilate to nearly its full size; and if either a full blown bladder, or a thin glass bubble filled with air, is held to a strong fire, it will burst. The elasticity of the air is such, that Mr. Boyle, by means of an air-pump, caused it to dilate until it occupied fourteen thousand times the space that it usually does. That the air is necessary to sound, flame, animal and vegetable life, is proved by the following experiments:—When the receiver of an air-pump is exhausted of its air, a cat, a mouse, or a bird, placed in it, expires in a few moments, in the greatest agonies. A bell rung in the same situation produces no sound; and a lighted candle is instantly extinguished. Similar experiments prove that air is necessary for the flight of birds, the ascent of smoke and vapors, the explosion of gunpowder, and the growth of plants; and that all bodies descend equally swift in a place void of air; a guinea and a feather being found to fall to the bottom of an exhausted receiver at the same instant.

On the principles which this science has established have been constructed the air-pump, the barometer, the thermometer, the diving-bell, the hygrometer, the condenser, and various other instruments, which have contributed to the comfort of human life, and to the enlargement of our knowledge of the constitution of nature.

IV. Acoustics.—This science treats of the nature, the phenomena, and the laws of sound, and the theory of musical concord and harmony.—From the experiments which have been made on this subject, we learn, that air is essential to the production of sound; that it arises from vibrations in the air, communicated to it by vibrations of the sounding body; that these vibrations, or aerial pulses, are propagated all around in a spherical undulatory manner; that their desity decreases as the squares of the distances from the sounding body increase; that they are propagated together in great numbers from different bodies without disturbance or confusion, as is evident from concerts of musical instruments; that water, timber, and flannel, are also good conductors of sound; that sound travels at the rate of 1142 feet in a second, or about thirteen miles in a minute;* that the softest whisper flies as fast as the loudest thunder; and that the utmost limits, within which the loudest sounds, produced by artificial means, can be heard, is 180 or 200 miles; that sound, striking against an obstacle, as the wall of a house, may, like light, be reflected, and produce another sound, which is called an echo; and that, after it has been reflected from several places, it may be collected into one point or focus, where it will be more audible than in any other place.

The intensity of sound increases or diminishes when the elasticity of the air increases or diminishes, either by heat or by compression. Hence, in proportion as the air is rarefied under the receiver of an air-pump, or in the ascent of lofty mountains, sound loses its force. Air communicates its vibrations to the sonorous bodies with which it is in contact. Hence a string of an instrument causes another stretched beside it to vibrate. A noise without makes the windows of an apartment to resound, and the discharge of can-nons, and peals of thunder, cause buildings, and even whole villages to shake. Euler tells us of a man who, by different inflections of his voice, made a glass vibrate so as almost to break it.—When the velocity of sound is known, the distance of certain objects may be determined. If a flash of a gun be observed, and the number of seconds or pulsations which elapse between seeing the flash and hearing the report, be counted, this number multiplied by 1142, the assumed velocity of sound per second, will give the distance of the observer from the center of vibration. If, in a thunder storm, I can count five pulsations, from the instant of seeing the lightning until the report of the thunder be heard, the distance of the thunder cloud will be 1142×5=5710 feet, that is, an English mile and 430 feet. Were the thunder to be heard within a second of the time of s[gap — reason: unclear]ing the flash, it would indicate that the thunder was within 380 yards of the observer, and consequently, that he is within the sphere of danger.—In estimating such distances 4 1/2 seconds, at an average, may be reckoned for every mile.

On the principles above stated we may account for the various phenomena of sounds and the diversified echoes which are heard in various places, which both amuse and sometimes puzzle the observers—and on the same principles whispering galleries, such as that in St. Paul's church, London, speaking and hearing trumpets—wind and stringed instruments—the Harmonica Celestina, and other acoustic instruments, are constructed.

V. Optics.—This branch of philosophy treats of vision, light, and colors, and of the various phenomena of visible objects produced by the rays of light, reflected from mirrors, or transmitted through lenses. From this science we learn, that light flies at the rate of nearly twelve millions of miles every minute—that it moves in straight lines—that its particles may be several thousands of miles distant from each other—that every visible body emits particles of light from its surface, in all directions—that the particles of light are exceedingly small; for a lighted candle will fill a cubical space of two miles every way with its rays, before it has lost the least sensible part of its substance; and millions of rays, from a thousand objects will pass through a hole not larger than the point of a needle, and convey to the mind an idea of the form, position, and color, of every individual object—that the intensity, or degree of light decreases, as the square of the distance from the luminous body increases; that is, at two yards distance from a candle, we shall have only the fourth part of the light we should have at the distance of one yard; at three yards distance, the ninth part; at four yards, the sixteenth part, and so on—that glass lenses may be ground into the following forms: plano-convex, plano-con-

* The velocity of sound has been somewhat differently estimated by different experimenters. Mr. Boyle estimated its velocity at 1200 feet; the Florentine Academicians at 1148 feet; the French Academicians at 1172 feet per second. It is reckoned by some modern philosophers that 1120 feet per second may be reckoned as a medium estimate. The experiments of Flamstead, Halley, and Derham, which were considered as having been accurately performed, give 1142 feet per second, as the average velocity of sound—which is sometimes modified by the direction of the wind and local circumstances.

In the war between England and Holland, in 1672, the noise of the guns was heard in those parts of Wales which were estimated to be two hundred miles distant from the scene of action. But the sounds produced by volcanoes have been heard at a much greater distance; some instances of which are stated in Chap. IV, Sect. 2. Several other facts, in relation to sound are detailed in Chap. III, Art. Acoustic Tunnels.

page 96 cave
, double convex, double concave
, and meniscus, that is, convex on one side, and concave on the other—that specula, or mirrors, may be ground into either a spherical, parabolical, or cylindrical form—that, by means of such mirrors and lenses, the rays of light may be so modified as to proceed either in a diverging, converging, or parallel direction, and the images of visible objects represented in a variety of new forms, positions, and magnitudes,—that every ray of white light may be separated into seven primary colors: red, orange, yellow, green, blue, indigo, and violet—that the variegated coloring which appears on the face of nature is not in the objects themselves, but in the light which falls upon them—that the rainbow is produced by the refraction and reflection of the solar rays in the drops of falling rain—that the rays of light are refracted, or bent out of their course, when they fall upon glass, water, and other mediums—that the light of the sun may be collected into a point or focus, and made to produce a heat more intense than that of a furnace*—that the rays from visible objects, when reflected from a concave mirror, converge to a focus, and paint an image of the objects before it, and that when they pass through a convex glass, they depict an image behind it.

On these and other principles demonstrated by this science, the Camera Obscura, the Magic Lantern, the Phantasmagoria, the Kaleidoscope, the Heliostata, the Micrometer—Spectacles, Opera Glasses, Prisms, single, compound, lucernal, and solar Microscopes, reflecting and refracting Telescopes, and other optical instruments, have been constructed, by means of which the natural powers of human vision have been wonderfully increased, and our prospects into the works of God extended far beyond what former ages could have conceived.

Connected with the science of Optics, it may be proper to notice a late discovery for fixing the images formed by convex lenses, distinguished by the name of the Daguerreotype. Almost every one knows the effects produced by the Camera Obscura. A convex glass placed in an opening in a window-shutter in a dark room, or in a box constructed for the purpose, forms, on a white screen, placed at its focal distance, a beautiful picture of all the objects which are opposite to it, in their exact proportions, symmetry, and colors. But this picture evanishes the moment the lens or the screen is removed. The Daguerreotype is an art by which this picture or image may be rendered permanent. It derives its name from M. Daguerre, a member of the French Academy of Fine Arts, who was in partnership with M. Neiper, who, as early as 1814, had commenced researches on this subject; but Daguerre had given up the idea of being able to bring his methods to perfection, until about the year 1838, when the effects produced by his art began to excite a considerable degree of attention; and as a reward for disclosing the process and publishing it to the world, the French government bestowed on the inventor and his partner an annuity of ten thousand francs (£416 13s. 4d.): M. Arago, when alluding to this discovery, has the following re mark: “No person has ever witnessed the neatness of outline, precision of form, the truth of coloring, and the sweet gradations of tint, dis played by the Camera, without regretting that an imagery so exquisite and so faithful to nature could not be made to fix itself permanently on the tablet of the machine—who has not put up his aspiration that some means might be discovered by which to give reality to shadows so lovely! Yet in the estimation of all, such a wish seemed destined to take its place among other dreams of beautiful things—among the glorious but impracticable conceptions in which men of science and ardent temperament have sometimes indulged. This dream, notwithstanding, has just been realized.”

Our limits will not permit to give a detail of the process by which the effect now stated is produced. We shall just state the following general outline.—The designs taken by the Daguerreotype are executed upon thin plates of silver plated on copper. The silver must be of the purest kind, and the thickness of both metals not to exceed that of a stout card. Before placing it in the Camera the following operations are requisite: 1. The plate must be cleansed and highly polished. For this purpose a little of fine pumice powder is put into a muslin bag and shaken over the plate, and it is then rubbed gently with cotton dipped in olive oil. Diluted nitric acid is then rubbed over the plate with cotton, and then rubbed again with pumice and dry cotton; and afterward the plate is to be subjected to a strong heat. 2. The plate has to receive a coating of Iodine. To accomplish this the plate is fixed upon a board, and then put into a box containing a little dish with iodine divided into small pieces, and allowed to remain until it is covered with a gold-colored coating, which process must be conducted in a darkened apartment 3. The Camera is next placed in the front of the landscape or object, and as soon as the focus is adjusted, the light is excluded, and the plate put in, when, in the course of a few minutes, and in some cases, in a few seconds, a perfect picture or design is obtained. I have seen a portrait of an individual taken in this way in the course of half a minute. 4. The plate is next placed over the vapor of mercury to bring out the image, which is not visible when withdrawn from the Camera The image is not visible until after the lapse of several minutes. 5. The coating on which the design was impressed is to be removed in order to preserve it from being decomposed by the rays of light. To do this, the plate is placed in a trough containing common water, plunging and with-drawing it immediately, and then plunging it into a solution of salt and water until the yellow coating has disappeared.

Such is a very abridged sketch of the photogenic operations of M. Daguerre. When finished in a perfect way, the designs thus taken on the plate are exceedingly beautiful and correct, and will bear to be inspected with a considerable magnifying power, so that the most minute portions

* This is produced by means of lenses, or mirrors, of a large diameter, called burning-glasses. By these instruments, the hardest metals, on which common fires, and even glass-house furnaces, could produce no effect, have been melted in a few seconds. M. Villette a Frenchman, nearly a century ago, constructed a mirror, three feet eleven inches in diameter, and three feet two inches in focal distance, which melted copper ore in eight seconds, iron ore in twenty-four seconds, a fish's tooth in thirty-two seconds, cast iron, in sixteen seconds, a silver sixpence in seven seconds, and tin in three seconds. This mirror condensed the solar rays 17,257 times, a degree of heat which is about four hundred and ninety times greater than common fire. Mr. Parker, of London, constructed a lens three feet in diameter, and six feet eight inches focus, which weighed 212 lbs. It melted twenty grains of gold in four seconds, and ten grains of platina in three seconds. The power of burning-glasses is, as the area of the lens directly, and the square of the focal distance inversely—or, in other words, the broader the mirror or lens, and the shorter the focal distance, the more intense is the heat produced by such instruments. A globular decanter of water makes a powerful burning-glass; and house furniture has been set on fire, by incautiously exposing it to the rays of the sun.

page 97 of the objects delineated may be perceived; and it has been discovered that an etching of the design can be taken in the common way, and from that again any number of electrotype copies can be produced. M. Claudet, the patentee of this invention at the Adelaide gallery, London, has made several improvements, particularly in taking likenesses. He is now enabled to take a likeness in one second, and even less—in the twinkling of an eye, and to give the portraits so made any background that may be desired.

This invention may be considered as still in its infancy; but in the course of its improvement, its results may be highly beneficial and extensive. To use the words of Arago: “To copy the millions of millions of hieroglyphics, which entirely cover to the very exterior of the great monuments at Thebes, Memphis, Carnoc, etc., would require scores of years and legions of artists. With the Dagnerreotype a single man would suffice to bring to a conclusion this vast labor; and at the same time, such designs shall incomparably surpass in fidelity, in truth of local color, the works of the ablest artists.” It is probable, too, that this art may be applied to taking exact pictures of the heavenly bodies—not only of the sun, but even of the moon, the planets, and the stars. The plated discs prepared by Daguerre receive impressions from the action of the lunar rays to such an extent as permits the hope that photographic charts of the moon may soon be obtained. Nor is it perhaps too much to expect that the rays of the stars—even of distant [gap — reason: unclear]ebulæ may thus be fixed and a delineation of their objects produced which shall be capable of being magnified by powerful microscopes.—This invention leads us to conclude that we have not yet discovered all the wonderful properties of that Light which un[gap — reason: unclear]ails to us the beauties and sublimities of the universe; and that thousands of admirable agencies and objects hitherto unknown, may soon be disclosed to our view through this medium, as we advance in our researches and discoveries.

VI. Electricity.—This name has been given to a science which explains and illustrates the operations of a very subtile fluid, called the electric fluid, which appears to pervade every part of nature, and to be one of the chief agents employed in producing many of the phenomena of the material world. If a piece of amber, sealing-wax, or sulphur, be rubbed with a piece of flannel, it will acquire the power of attracting small bits of paper, feathers, or other light substances. If a tube of glass, two or three feet in length, and an inch or two in diameter, be rubbed pretty hard, in a dark room, with a piece of dry woolen cloth, beside attracting light substances, it will emit flashes of fire, attended with a crackling noise. This luminous matter is called electricity, or the electric fluid. If a large globe, or cylinder of glass, be turned rapidly round, and made to rub against a cushion, streams and large sparks of bluish flame will be elicited, which will fly round the glass, attract light bodies, and produce a pungent sensation, if the hand be held to it. This glass, with all its requisite apparatus, is called an electrical machine. It is found that this fluid will pass along some bodies, and not along others. The bodies over which it passes freely are water, and most other fluids, except oil and the aerial fluids; iron, copper, lead, and in general all the metals, semi-metals, and metallic ores; which are therefore called conductors of electricity. But it will not pass over glass, resin, wax, sulphur, silk, baked woods, or dry woolen substances; nor through air, except by force, in sparks, to short distances. These bodies are therefore called nonconductors.

The following facts, among others, have been ascertained respecting this wonderful agent:—That all bodies with which we are acquainted possess a greater or less share of this fluid—that the quantity usually belonging to any body produces no sensible effects; but when any surface becomes possessed of more or less than its natural share, it exhibits certain appearances in the form of light, sound, attraction, or repulsion, which are ascribed to the power called electric — that there are two different species of the electrical fluid, or at least two different modifications of the same general principle, termed positive and negative electricity—that positive and negative electricity always accompany each other; for if a substance acquire the one, the body with which it is rubbed acquires the other—that it moves with amazing rapidity, having been transmitted through wires of several miles in length, without taking up any sensible space of time; and therefore it is not improbable, that were an insulated conducting substance extended from one continent to another, it might be made to fly to the remotest regions of the earth in a few seconds of time*—that it has a power of suddenly contracting the muscles of animals, or of giving a shock to the animal frame—that this shock may be communicated, at the same instant, to a hundred persons, or to any indefinite number who form a circle, by joining their hands together—that it may be accumulated to such a degree as to kill the largest animals—that vivid sparks of this fluid, attended with a crackling noise, may be drawn from different parts of the human body, when the person is insulated, or stands upon a stool supported by glass feet—that electricity sets fire to gunpowder, spirits of wine, and other inflammable substances—that it melts iron wire and destroys the polarity of the magnetic needle—that it augments the natural evaporation of fluids, promotes the vegetation of plants, and increases the insensible perspiration of animals; and can be drawn from the clouds by means of electrical kites, and other elevated conductors. By means of the electrical power, small models of machinery have been set in action; orreries to represent the movements of the planets have been put in motion; and small bells have been set ringing for a length of time; and, in consequence of the knowledge we have acquired, of the mode of its operation in the system of nature, the lightnings of heaven have been arrested in their course, and constrained to descend to the earth, without producing any injurious effects.

From these, and a variety of other facts and experiments, it is now fully ascertained, that lightning and electricity are identical; and that it is the prime agent in producing the awful phenomena of a thunder-storm; the lightning being the rapid motion of vast masses of electric matter, and thunder the noise, with its echoes, produced by the rapid motion of the lightning through the atmosphere.—There can be little doubt that in combination with steam, the gases, and other agents, it also produces many of the terrific phenomena of earthquakes, volcanoes, whirlwinds, water-spouts, and hurricanes, and the sublime coruscations of the aurora borealis.—In the operations of this powerful fluid, we behold a striking display of the sovereignty and majestic agency of God. In directing its energies, “his way is in the whirlwind and the storm, and the clouds are

* See Chap. III, Art. Electric Telegraph.

page 98 the dust of his feet; the heavens are covered with sackcloth, the mountains quake before him, the hills melt, the earth is burned at his presence, and rocks are thrown down by him.”* It is easy to conceive, that by a few slight modifications produced by the hand of Omnipotence, this powerful fluid might become the agent of producing either the most awful and tremendous, or the most glorious and transporting scenes, over every region of our globe. As it now operates, it is calculated to inspire us rather with awe and terror than with admiration and joy; and to lead our thoughts to a consideration of the state of man as a depraved intelligence, and a rebel against the government of his Maker.

Electricity is rapidly extending its boundaries, and its influence as an important agent in the arts; and, as yet, we can form no adequate conception of the results which may flow from the investigations into its nature, combinations, and applications, which are now making by the scientific world, or of the powerful effects it may produce, when thoroughly wielded by the hand of genius. It has already been applied to many useful purposes—to remove obstructions in the human frame—to cure diseases—to ascertain the depths of the sea—to produce explosions for effecting mechanical operations,—and for conveying intelligence at the rate of 192,000 miles in a second. Among its recent applications is the pro[gap — reason: unclear][gap — reason: unclear]ss of copying with perfect accuracy engraved copperplates, medals, seals, etc.—and of gilding, plating, and etching, with great beauty and precision. This art has been denominated Electrotype, and was discovered by Mr. Thomas Spencer, of Liverpool, in 1839. It was also discovered on the Continent by Professor Jacobi. The materials recommended by him for forming the molds on which impressions are taken are fusible metal, wax, and stearine. When a copy is taken from any copperplate or medal, any number of copies can be produced equally as good as the first. The process is simple, but our limits will not permit to enter into its details. The reader will find a short description of the process in Chambers’ “Information for the People,” No. 57, Art. Electricity, etc., and in the “Practical Mechanic and Engineer's Magazine,” vol. i, p. 227.

An important combination of the Electrotype with the Daguerreotype process has lately been discovered, which promises to lead to some important results. A Daguerreotype picture can be produced in the ordinary way, as formerly described—it can be etched according to the present process, and from this etching an indefinite number of electrotype copies can be obtained. As an illustration of the perfection attendant on this process, the inventor states that, from a Daguerreotype plate which had on it a sign-board measuring 1–10th by 6–100ths of an inch, five lines of the inscription can be distinctly read by the aid of a microscope applied to the electrotype copy. So that, as the author remarks, “instead of a plate being inscribed as drawn by Landseer, and engraved by Cousins, it may be said, drawn by Light and engraved by Electricity.”

VII. Galvanism is intimately connected with electricity, though it is generally considered as a branch of Chemistry. It is only another mode of exciting electrical action. In electricity the effects are produced chiefly by mechanical action; but the effects of Galvanism are produced by the chemical action of bodies upon each other. If we take a piece of zinc, and place it under the tongue, and lay a piece of silver, as big as a half-crown, above it; by bringing the outer edges of these pieces in contact, we shall immediately experience a peculiar and disagreeable taste, like that of copper. The same thing may be noticed with a guinea and a piece of charcoal. If a person, in the dark, put a slip of tinfoil upon one of his eyes, and a piece of silver in his mouth, by causing these pieces to communicate, a faint flash will appear before his eyes. If a living frog or a fish, having a slip of tinfoil pasted upon its back, be placed upon a piece of zinc, by forming a communication between the zinc and tinfoil, the spasms of the muscles are excited. These and similar effects are produced by that modification of electricity which has been termed Galvanism. Three different conductors, or what is called a galvanic circle, are requisite to produce such effects. A piece of copper, a piece of flannel, moistened with water or acid, and a piece of zinc, laid upon one another, form a circle; and if this circle be repeated a number of times, a galvanic pile or battery may be formed, capable of giving a powerful shock. The most common and convenient form, however, of a battery, is found to be a trough of baked wood, three or four inches deep, and as many wide. In the sides are grooves, opposite to each other, into each of which is placed a double metallic plate of zinc and copper soldered together, and the cells are then filled either with salt and water, or with a solution of nitrous acid and water.

By means of the galvanic agency, a variety of surprising effects have been produced. Gunpowder, cotton, and other inflammable substances have been inflamed—charcoal has been made to burn, with a most brilliant and beautiful white flame—water has been decomposed into its elementary parts—metals have been melted and set on fire—fragments of diamond, charcoal, and plumbago, have been dispersed, as if they had been evaporated—platina, the hardest and heaviest of the metals, has been melted as readily as wax in the flame of a candle—the sapphire, quartz, magnesia, time, and the firmest compounds in nature, have been made to enter into fusion.—Its effects on the animal system are no less surprising. When applied to a fowl or a rabbit, immediately after life is extinct, it produces the most strange and violent convulsions on the nervous and muscular system, as if the vital functions were again revived: and when applied to the human body after death, the stimulus has produced the most horrible contortions and grimaces in the muscles of the head and face; and the most rapid movements in the hands and feet.

Numerous experiments which have been made both on dead animals and on human subjects, have led to the conclusion that galvanism possesses some sanative as well as energetic influence on the actions of diseased living beings. It has been found to effect cures, and to afford relief in nervous disorders. It has not only been used to cure the afflicted living, but also to resuscitate the apparently dead; and in all cases of suspended animation, from accidents or otherwise, it has been found to be a test of vitality, and the surest criterion of recent death. A celebrated medical writer on this subject, in Berlin, strongly recommends its use in rheumatism, palsies, nervous deafness, hoarseness, debility of sight, white swellings of the joints, tumors in the glands of the neck, and several other disorders. It is found that it possesses not only a stimulating power over the nerves and muscles, but also over the vital forces. M. Spronger, of Jena, gives an ac-

* Nahum, i. 3–6.

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of his having restored the sense of hearing to 45 persons, by means of this singular agent—to four of whom he also restored the sense of smelling.—Galvanism has been lately employed as a powerful agent for blasting rocks. At Glasgow, and several other places, its agency has been applied with great success. At one blast hundreds of tons of stones have been in a moment loosened from the rock. It is found that dry sand is quite sufficient for filling the perforation in the rock where the charge is placed, and that the whole process is unaccompanied with the smallest degree of danger, so that, by this mode of blasting, those accidents which have so frequently happened to workmen employed in such operations may be entirely prevented.

The galvanic agency enables us to account for the following, among other facts:—Why porter has a different and more pleasant taste when drunk out of a pewter vessel than out of glass or earthenware,—why a silver spoon is discolored when used in eating eggs,—why the limbs of people, under amputation, are sometimes convulsed by the application of the instruments,—why pure mercury is oxydized when amalgamated with tin,—why works of metal, which are soldered together, soon tarnish in the places where the metals are joined,—and why the copper sheathing of ships, when fastened with iron nails, is soon corroded about the place of contact. In all these cases a galvanic circle is formed which produces the effects. We have reason to believe that, in combination with the discoveries which modern chemistry is daily unfolding, the agencies of this fluid will enable us to carry the arts forward toward perfection, and to trace the secret causes of some of the sublimest phenomena of nature.

VIII. Magnetism.—This department of philosophy describes the phenomena and the properties of the loadstone, or natural magnet. The natural magnet is a hard dark-colored mineral body, and is usually found in iron mines. The following are some of its characteristic properties:—1. It attracts iron and steel, and all substances which contain iron in its metallic state. 2. If a magnet be suspended by a thread, or nicely poised on a pivot, or placed on a piece of wood, and set to float in a basin of water, one end will constantly point nearly toward the north pole of the earth, and the other toward the south; and hence, these parts of the magnet have been called the north and south poles. 3. When the north pole of one magnet is presented near to the south pole of another, they will attract each other; but if the north pole of one be presented to the north pole of another, or a south pole to a south, they will repel each other. 4. A magnet placed in such a manner as to be entirely at liberty, inclines one of its poles to the horizon, and of course elevates the other above it. This property is called the dipping of the magnet. 5. Magnets do not point directly north and south; but in different parts of the world with a different declination eastward or westward of the north: it is also different at the same place at different times. In London, and in most places of Great Britain, the magnetic needle in 1824 pointed about 24 degrees to the west of the north. For more than 160 years previously it had been gradually declining from the north to the west; but seemed then to have begun its declination to the eastward. 6. Any magnet may be made to communicate the properties now mentioned to any piece of iron or steel. For example, by gently rubbing a penknife with a magnet, it will be immediately invested with the property of attracting needles, or small pieces of iron or steel. 7. Heat weakens the power of a magnet, and the gradual addition of weight increases the magnetic power. 8. The properties of the magnet are not affected either by the presence or the absence of air; and the magnetic attraction is not in the least diminished by the interposition of any bodies except iron. A magnet will equally affect the needle of a pocket compass, when a thick board is placed between them, as when it is removed. It has been lately discovered, that the violet rays of the solar spectrum, when condensed with a convex glass, and made to pass along a piece of steel, have the power of communicating to it the magnetic virtue.

The cause which produces these singular properties of the magnet has hitherto remained a mystery; but the knowledge of the polarity of the magnet has been applied to a most important practical purpose. By means of it, man has now acquired the dominion of the ocean, and has learned to trace his course through the pathless deep to every region of the globe. There can be little doubt, that magnetism has an intimate connection with electricity, galvanism, light, heat, and chemical action; and the discoveries which have been already made, and others to be expected, from the experiments of Morichini, Oersted, Abraham, Hansteen, Barlow, Beaufoy, Ampère, and Scoresby, promise to throw some light on this mysterious agent, and on the phenomena of nature with which it is connected.

Electro–Magnetism.—This is a new science founded on the connection which is now ascertained to subsist between Electricity and Magnetism. In the year 1819, Professor Oersted of Copenhagen discovered that, when a wire conducting electricity is placed parallel to a magnetic needle, properly suspended, the needle will deviate from its original or natural direction. 1. If the needle be above the conducting wire, and the positive electricity goes from right to left; the north end of the needle will be moved from the observer, or to the west. 2. If the needle is below the wire, and the electricity passes as before, the north end of the needle will be moved toward the observer or to the east. 3. If the needle is in the same horizontal plane with the wire, and is between the observer and the wire, the north end of it will be elevated. 4. If the needle is similarly placed on the opposite side, the north end of it will be depressed. From these facts M. Oersted concludes, that the magnetical action of the electrical current has a circular motion round the wire which conducts it.—When these experiments were commenced, and repeated, and varied by other philosophers, a multitude of new facts were soon brought to light through the labors of Davy, Faraday, Ampère, Barlow, Biot, and other experimenters. Two very important facts were ascertained by Ampère and Davy—that the conjunctive wire itself becomes a magnet—and that magnetic properties might be communicated to a steel needle not previously possessing them, by placing it in an electrical current. The former of these facts is proved by throwing iron filings on paper and bringing them under the wire, when they will immediately adhere to it, forming a tuft round it 10 or 12 times the diameter of the wire. On breaking the connection with the battery, however, they immediately fall off, proving that the magnetic effect depends entirely on the passage of the electricity through the wire. The degree of force of the magnetic property thus communicated to the uniting wire, is considered by Sir H. Davy, to be proportional to the quantity of electricity transmitted through it Hence the page 100 finer the wire the more powerfully magnetic was it rendered; and hence also a battery of very large plates was found to give the strongest magnetism to the wire connecting its poles.

The following are some of the results of experiments which have been made on this subject;—1. The deviation of the magnetized needle is greater or less, according to the nature of the conducting wire; and copper appears to be of all metals that which produces the most powerful effects. 2. The intensity of an electrical current is constant throughout the whole of a homogeneous wire whatever may be its length. 3. If two homogeneous conductors be simultaneously adapted to the same galvantic pile—first, the absolute intensity of the current decreases in the inverse ratio of the square root of the length of the wire—and secondly, when the thickness of the wires is altered, the intensity of the current increases with their diameter to a certain limit, beyond which an increase of thickness no longer produces any change in the intensity of the current. 4. When the conjunctive wires of two distinct galvanic arrangements are made to approach each other, magnetic attractions and repulsions are observed. Two wires of copper, silver, or any other metal, connecting the extremities of two galvanic troughs, being placed parallel to each other, and suspended so as to move freely, immediately attract and repel each other, according as the directions of the currents of electricity flowing through them are the same or different.—On this experiment is founded the most plausible and rational theory of magnetism, namely, that it arises from the attractions and repulsions of currents of electricity constantly circulating round every magnet. This is considered as explaining the reason why the magnetic needle places itself at right angles to a wire conducting electricity, namely, that the electric current passing along the wire may coincide with that circulating round the magnet.

These, and a great number of other facts, it is presumed, clearly demonstrate the perfect resemblance, or rather identity, of electricity and magnetism. Magnetic phenomena are thus, in fact, a series of electrical phenomena, and magnetism may, with propriety, form a branch of electricity, under the head of Electrical currents. Currents of electricity, according to this theory, are essential to the production of magnetic phenomena; but these are not obvious in a common magnet. M. Ampère has suggested their existence, however, and has so arranged them theoretically, as to account for a great proportion of magnetic appearances. A magnet, he conceives, to be an assemblage of as many electrical currents moving round it in planes perpendicular to its axis, as there may be imagined lines, which, without cutting one another, form closed curves round it. A permanent magnet, then, may be conceived to be a mass of iron or steel round the axis of which electric currents are continually circulating, and these currents attract all other electric currents flowing in the same direction, and repel all others which are moving in an opposite direction. One important circumstance is always to be kept in view, that the electric currents flow round every magnet in the same direction in reference to its poles. If, for instance, we place a magnet with its north pole pointing to the north, in the usual position of the magnetic needle, the current of electricity flows round it from west to east—or in the direction in which the planets revolve, and the earth on its axis—or on the western side of the magnet It is moving upward, and on the eastern side downward; on the upper side from west to east, and on the lower side from east to west. This is ascertained to be a uniform law, and on these principles most of the phenomena of magnetism may be accounted for.

To complete the view of Ampère's doctrine on this point, it remains only to explain the influence of the earth on the magnet by which the needle is kept always in one position, nearly coinciding with the meridian. He maintains that currents of electricity, analogous to those which circulate round every magnet, are constantly floating round the globe, as the current of electricity in a galvanic apparatus moves in an unbroken circuit from the negative to the positive pole, and from it, by the connecting wire, round again to the negative pole. The direction of these currents he infers to be the same as has been stated with artificial magnets; and it is simply by the attractions and repulsions of these terrestrial currents, bringing the currents round the needle to coincide with them, that the latter always points to the north. The cause of these electric currents thus inferred to be constantly circulating round the globe, is, as yet, involved in obscurity. They are supposed to move at right angles to the magnetic meridian, or nearly parallel with the equator, on the eastern side of the earth moving from us, and on the western side flowing toward us. It is conjectured that the arrangement of the materials of the globe may be such as to constitute a battery, existing like a girdle round the earth, which, though composed of comparatively weak materials, may be sufficiently extensive to produce the effects of terrestrial magnetism. Its irregularity, and the changes it may accidentally or periodically suffer, may explain the phenomenon of the variation of the compass;—or the general action producing the currents of electricity may be affected by different causes, as the motions of the earth, the currents of the atmosphere, the process of evaporation, and the solar heat. It may also be supposed that much of the variation depends on the progress of oxydation in the continental regions of the globe.

In connection with the principles and phenomena stated above,—by means of a galvanic battery, iron may be temporarily magnetized—in other words, endowed with an attractive power, so long as it is kept in connection with the galvanic apparatus A magnet of this kind is generally formed in the shape of a horse-shoe; and when suspended so as to present the extremities downward, and when the galvanic communication is established, the magnetic power is instantly exerted, and a bar of iron held to the extremities will be immediately attracted, and firmly adhere. But, on loosening the connection with the battery, the magnetic power is instantly destroyed, and the ball of iron falls to the ground. Such magnets, which have obtained the name of Electro–megnets, have been thus made, endowed with very great attractive power, so as to sustain, in some cases, a weight of above 2000 pounds, or nearly a ton. These magnets, like those which possess permanent magnetism, have opposite poles, one attracting, and the other repelling.

This new science of Electro-magnetism has opened up new and more expansive views to the philosophic world, in reference to the powers of Electricity, Galvanism, and Magnetism, and their relation to each other; and in the progress of the investigations which are now going forward, we have reason to hope that some of the hitherto latent principles which pervade our terrestrial system will be unfolded, and the diversified phenomena they produce more fully explained and illus- page 101 trated. It is probable, too, that the arts will be improved by the application of the principles which this science has brought to light; and they have already been applied to machinery to produce rotatory and impulsive motions.

Such is a faint outline of some of the interesting subjects which Natural Philosophy embraces. Its relation to Religion will appear from the following considerations:—

1. Its researches have led to the invention of machines, engines, and instruments of various kinds, which augment the energies, increase the comforts, and promote the general improvement of mankind; and these objects are inseparably connected with the propagation of Christianity through the world. If we admit that, in future ages, the religion of the Bible will shed its benign influence over all nations—that the external condition of the human race will then be prosperous and greatly meliorated beyond what it has ever been—and, that no miraculous interposition of Deity is to be expected to bring about such desirable events—it will follow, that such objects can be accomplished only, in the ordinary course of Providence, by rational investigations into the principles and powers of Nature, and the application of the inventions of science to the great objects of religion, and of human improvement, as I shall endeavor briefly to illustrate in the following chapter. As the destructive effects of many physical agents, in the present constitution of our globe, are, doubtless, a consequence of the sin and depravity of man—we have reason to believe, that, when the economy of nature shall be more extensively and minutely investigated, and the minds of men directed to apply their discoveries to philanthropic and religious objects, they will be enabled to counteract, in a great measure, those devastations and fatal effects which are now produced by several of the powers of nature. The general happiness of all ranks, which will be connected with the universal extension of Christianity, necessarily supposes that this object will be accomplished; for, were a dread of destruction from the elements of nature frequently to agitate the mind, as at present, no permanent tranquillity would be enjoyed; nor would that ancient prediction in reference to this era, receive its full accomplishment, that “there shall be nothing to hurt or destroy in all God's holy mountain, when the earth shall be full of the knowledge of the Lord.” And since miraculous interpositions are not to be expected, to what quarter can we look for those subordinate agencies by which this object is to be effected, but to the discoveries and inventions of philosophical science?

Science has already enabled us to remedy many of those evils which are the accidental effects of the operation of physical agents. For example—the discoveries of the philosopher, with respect to the nature of the electric fluid, have enabled us to construct conductors for preserving buildings from the stroke of lightning; and we have every reason to hope, that, in the progress of electric, galvanic, and chemical science, more complete thunderguards, applicable to all the situations in which a person may be exposed, will be invented. Nay, our increasing knowledge of the electric fluid, and of the chemical agents which concur in its operation, may enable us to dissipate thunder-storms altogether, by disturbing the electricity of the clouds, by means of a series of elevated artificial conductors. This is not only possible, but has already been in some degree effected. The celebrated Euler informs us, in his “Letters to a German Princess,” that he corresponded with a Moravian priest, named Divisch, who assured him, “that he had averted, during a whole summer, every thunder-storm which threatened his own habitation and the neighborhood, by means of a machine constructed on the principles of electricity—that the machinery sensibly attracted the clouds, and constrained them to descend quietly in a distillation, without any but a very distant thunderclap.” Euler assures us, that “the fact is undoubted, and confirmed by irresistible proof.” Yea, not only may the destructive effects of lightning be averted by the inventions of philosophy, but its agency may be rendered subservient to human industry, and made to act as a mechanical power. This effect, too, has been partially accomplished. About the year 1811, in the village of Philipsthal, in Eastern Prussia, an attempt was made to split an immense stone into a multitude of pieces, by means of lightning. A bar of iron, in the form of a conductor, was previously fixed to the stone, and the experiment was attended with the most complete success; for, during the very first thunder-storm, the lightning burst the stone without displacing it.*

It is, therefore, probable that, in the future ages of the world, this terrific meteor, and other destructive agents, which now produce so much alarm, and so many disastrous effects, may, by the aid of philosophy, be brought under the control of man, and be made to minister to his enjoyment.

The electric fluid has also been, in many instances, successfully applied in curing palsies, rheumatisms, spasms, obstructions, and inflammation; and it is known to have a peculiar effect on the nervous system. Lightning has been known to restore the blind to a temporary enjoyment of sight. Mr. Campbell, of Succouth, in Dunbartonshire, who had been blind for several years, was led by his servant one evening through the streets of Glasgow, during a terrible thunderstorm. The lightning sometimes fluttered along the streets for a quarter of a minute without ceasing. While this fluttering lasted, Mr. Campbell saw the street distinctly, and the changes which had been made in that part by taking down one of the city gates. When the storm was over, his entire blindness returned.—The following instance, stated by Professor Robison, as related by one of his friends, is no less remarkable. One evening in autumn, he was sitting with a gentleman who had the same disorder as the gentleman mentioned above, and he observed several lambent flashes of lightning. Their faces were turned to the parlor window; and immediately after a flash, the gentleman said to his wife, “Go, my dear, make them shut the white gate; it is open, you see.” The lady did so, and returned; and, after a little, said, “But how did you know that the gate was open?” He exclaimed, with wonder, “I saw it open, and two men look in, and go away again”—which our friend also had observed—the gentleman, on being close-questioned, could not recollect having had another glance, nor why it had not surprised him; but of the glimpse itself he was certain, and described the appearance very exactly.

It is also possible, that barren deserts might be enriched with fertility, and immense portions of the desolate wastes of our globe prepared for the support and accommodation of human beings, by arresting the clouds, and drawing down their elec-

* See Monthly Magazine, vol. xxii, p. 162.

Sup. to Ency. Brit., 3d dit., Art., Thunder—written by the late Dr. Robison.

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virtue and their watery treasure, by means of an extended series of elevated metallic conductors. What has been now stated, is only one instance out of many which might be produced, of the extensive and beneficial effects which may be produced, in future ages, by the application of the discoveries of natural science.

2. A knowledge of Natural Philosophy enables us to detect pretended miracles, and to discriminate between those phenomena which are produced by the powers of nature, and the supposed effects of diabolical influence. It has been chiefly owing to ignorance of the principles of natural science, that mankind, in all ages, have been so easily imposed upon by pretenders to supernatural powers. It is owing to the same cause, that superstitious notions and vain alarms have spread their influence so extensively among the lower ranks of the population of every country. The pretended miracles by which Pagan and Popish priests endeavor to support the authority of their respective religious systems, and every species of degrading superstition, vanish into smoke, when examined by the light of modern science; and there can be no question, that an enlightened Missionary would, in many instances, find the principles and the instruments of natural philosophy important auxiliaries in undermining the fabric of heathen idolatry and priestcraft. They tend to dissipate a thousand idle terrors which haunt and agitate the human mind; to detect a thousand kinds of imposture by which it has been held in cruel bondage; and to prevent the perpetration of those deeds of cruelty which have uniformly marked the reign of Superstition.* Had our forefathers connected a knowledge of this subject with their study of the Scriptures, they would not have brought upon themselves that indelible disgrace which now attaches to their memories, on account of their having condemned and burned at the stake thousands of unhappy women, accused of crimes of which they could not possibly have been guilty. In New England, toward the close of the 17th century, the witchcraft frenzy rose so high, that the execution of witches became a calamity more dreadful than the sword or the pestilence. Not only old women, but children of ten years, were put to death; young girls were stripped naked, and the marks of witchcraft searched for upon their bodies with most indecent curiosity; and those spots of the scurvy which age impresses upon the bodies of old men were taken for evident signs of infernal power. So that ignorance of the laws and phenomena of nature has led even Christians to commit acts of injustice and horrid cruelty. For, let it be remembered that it was Christian magistrates and ministers, under a pretended zeal for the honor of God, who sanctioned such cruel and unrighteous decrees. This consideration, viewed in connection with many others, tends to show, that the Christian revelation, considered abstractly by itself, without a reference to the visible system of the universe, is not sufficient for all the purposes for which it was intended; as, on the other hand, the study of the works of nature is not sufficient of itself to lead the mind to the true knowledge of God, without the aid of the discoveries derived from the sacred oracles. For, although the Bible has been in the hands of Protestant Christians ever since the Reformation, yet it is only since the light of modern science began to diffuse its influence, that the superstitions of the dark ages, and the vulgar notions respecting witchcraft, necromancy, and other species of infernal agency, began to evanish, even from the minds of Christian teachers; as is evident from the writings of many eminent divines who flourished during the 16th and 17th centuries. As the two revelations which God has given throw a mutual luster on each other, the one must always be considered as incomplete without the other. Both are necessary, in order “to make the man of God perfect,” and to enable him to prosecute, with intelligence and success, the great objects of religion; and the Christian minister who affects to despise the aids of science in the cause of religion has yet much to learn with respect to some of the grand bearings of the Christian system.

3. The investigations of natural philosophy unfold to us the incessant agency of God, and the plans by which his wise and benevolent designs in the system of nature are accomplished. From the immeasurable globes of heaven, down to the minutest atoms, we perceive a regular chain of causes and effects, conspiring, in a thousand different modes, to accomplish the purposes of infinite wisdom and goodness. The operation of central forces, and of the law of gravitation on the earth, and in the heavens—the hydrostatical laws which regulate the pressure and the motion of fluids—the chemical properties of the atmosphere, its undulatory, refractive, and reflective powers—the motion of the rays of light, and the infinite variety of effects they produce—the process of evaporation—the agencies of electricity and galvanism—the properties of the magnet, and the chemical action of acids and alkalies, and of the minutest particles of matter upon each other,—ought to be viewed as so many modifications of the agency of Deity, and as manifestations of his wisdom, in carrying forward those plans which regard the interests of his universal kingdom; just as we consider the rise and fall of empires, the revolutions of nations, and the circulation of the Scriptures in heathen lands, as so many acts of his moral administration as the Governor of mankind. For, let it be carefully remembered, that all these physical agencies have ultimately a moral and intellectual bearing; and are essentially connected with every other part of God's providential procedure. Though we may be apt to consider them as so many detached and insulated pieces of machinery, with which we have little concern, or may even disdain to notice their mode of operation; yet, in the all-comprehensive mind of Him who takes in, at one glance, the whole chain of causes and effects, they are as essentially con-

* Mr. Douglas, in his “Hints on Missions,” suggests, that Natural Philosophy might be an important auxiliary to Christian Missionaries. “All the ancient ‘war weapons of victory,’ excepting miracles, are at their disposal; and new instruments of still greater potency, which the science of the latter days has been accumulating for universal revolution of the mind are ready to be brought into action, upon a scale of overpowering magnitude. Even the single resource which is lost may yet be recompensed by equivalents, and a substitute, in many respects, may be found for miracles. The first effect of a miracle is, to rouse the attention, and to overawe opposing prejudices; the second, to afford a proof of religion of which it is a sealing accompaniment.—The first object might be gained by the natural magic of experimental philosophy; and as to the second, the difference in the proof from miracles, lies rather in its being more circuitous, than in its being less conclusive at the present day, than in the times of the Apostles.” Mr. Moffat, missionary from Africa, lately expressed to the author sentiments similar to the above, and intimated his ardent desire that he might be furnished, before his return, with an apparatus for the purpose of expanding the minds of heathen converts in the knowledge of nature.

It has been calculated that, in Germany alone, the number of victims that suffered for the supposed crime of witchcraft from 1484—the date of the bull of Pope Innocent VIII, against witchcraft—until the beginning of the eighteenth century, considerably exceeds one hundred thousand!

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with his ultimate purposes, and the eternal destiny of man, as are the revelations of his word.—Were a single principle or motion which now animates the system of nature to cease—were the agency of electricity, for example, or the principle of evaporation, to be destroyed—the physical constitution of our globe would instantly be deranged; nature would be thrown into confusion; and the sentient and intellectual beings that now inhabit the earth would either be destroyed, or plunged into an abyss of misery. If therefore we admit, that the moral agency of God is worthy of our contemplation, we ought to consider his physical operations also as no less worthy of our study and investigation; since they form the groundwork of all his other manifestations.

There is nothing, however, which so strikingly characterizes the bulk of mankind, and even the great mass of the Christian world, as that apathy and indifference with which they view the wonders of creation which surround them. They can look on all that is grand and beautiful and beneficent in nature, without feeling the least sentiment of admiration or of gratitude to that Being who is incessantly operating within them and around them; and they are disposed to consider the experiments of philosophers, by which the wonderful agency of God is unvailed, as only so many toys and amusements for the entertainment of children. They would prefer the paltry entertainments of a card-table, of a ball-room, or of a gossiping party, to the inspection of the nicest pieces of Divine mechanism, and to the contemplation of the most august scene in nature. However lightly some religionists may be disposed to treat this subject, that spirit of indifference with which the visible works of God are treated must be considered as flowing from the same depraved principle, which leads multitudes to reject the revelations of the Bible, and to trifle with their everlasting interests. “Man,” says Rollin, “lives in the midst of a world of which he is the sovereign, as a stranger, who looks with indifference upon all that passes in it, and as if it were not his concern. The universe, in all its parts, declares and points out its Author; but, for the most part, to the deaf and blind, who have neither ears to hear, nor eyes to see. One of the greatest services that philosophy can do us, is to awaken us from this drowsiness, and rouse us from this lethargy, which is a dishonor to humanity, and in a manner reduces us below the beasts, whose stupidity is the consequence of their nature, and not the effect of neglect or indifference. It awakens our curiosity, it excites our attention, and leads us, as it were, by the hand, through all the parts of nature, to induce us to study and search out the wonderful works of it.”*

Since, therefore, the science of natural philosophy is conversant about the works of the Almighty, and its investigations have a direct tendency to illustrate the perfections of his nature, to unvail the plan of his operations, to unfold the laws by which he governs the kingdom of universal nature, and to display the order, symmetry, and proportion, which reign throughout the whole—it would be needless to enter into any further process of reasoning, to show that the study of it is connected with the great objects of religion.—Whatever studies tend to raise our minds to the Supreme Ruler of all worlds—to expand our views of his infinite knowledge and wisdom—to excite our gratitude and our admiration of the beneficent designs which appear in all his arrangements—to guard us against erroneous conceptions of his providential procedure—and to furnish us with important auxiliaries for extending the influence of his religion through the world—must always be interesting to every Christian who wishes to enlarge his intellectual views, and to make progress in the knowledge of God.

* Belles Lettres, vol. iv.