Electric Force.

"F.I.R.S." Relates how he witnessed in Paris, on the 9th of May, the charging of four of Faure's batteries with electricity obtained from an ordinary Grove's battery. The four batteries were enclosed in a wooden box, about a cubic foot in measurement, and weighing, with its contents, about 75lb. This box of "electric energy" was handed by M. Faure to our correspondent, who brought it with him across the Channel, and after 72 hours of travelling, delivered it to Sir William Thomson at Glasgow, in order that the power of its charge might be made the subject of observation and experiment. The box was believed to contain electricity in quantity equivalent to a million foot pounds; and we now hear that this belief has been fully borne out by experiment. No appreciable loss was incurred during the transit; and the energy put into the four batteries in Paris remained in them until it was applied to working purposes in Glasgow. So completely was the apparatus under command, that one of the four batteries was detached from the rest, and carried to another place to supply the force required for an electric cautery. A single battery, when recharged, was left alone for ten days, and it then yielded to Sir William Thomson 260,000 foot pounds, so that the original estimate of a million foot pounds for the whole box was probably somewhat under the mark. Further investigations are required in order to discover what are the limits, if any, of the power to preserve electric energy unwasted; but sufficient is known to show that it can be preserved long enough for many important practical applications. That which Sir William Thomson regards as likely to be the first, at least in point of time, is the use of Faure's batteries in private houses, as reservoirs of electricity for domestic purposes, such as lighting, heating, working sewing machines, so that no interruption of action would be produced by a temporary interruption of the electric supply given by any main engine from which it was derived.

Sir William Thomson reminds us that the storage of force to be afterwards put to practical uses is a very old contrivance, of which we may see an illustration in the winding of a watch; and also that the storage of electricity has long been familiar to men of science as a theoretical possibility. There is often a long step, however, from theoretical possibility to practical achievment; and what we are now called upon to notice is no longer that such a storage may perhaps be page 3 accomplished at some future time, but that it has actually been accomplished upon what may almost be called a working scale. Many philosophers are of opinion that electricity, at no distrnt date, will entirely supersede fires for cooking and heating, steam as a motor, and gas and oil as illuminants; but hitherto it has been felt as a great difficulty, economical rather than scientific, that the agents proposed to be superseded were themselves actually employed to produce the electricity. It has been asserted, moreover, that the sectional area of the metallic conductors required to deliver electricity in quanties suited to the requirements of town communities would have to be enormously large, and in a corresponding degree costly; and that difficulties with regard to insulation would be of constant occurrence. But electricity is to be obtained from the atmosphere by simple mechanical means wherever any kind of motor power is available; and, if it can be stored in portable batteries and carried about for use, there seems to be no reason why it should not be obtained in very cheap ways, as by wind or water mills, and by mechanical contrivances for utilizing the ebb and flow of the tides, or by other applications of the power which nature everywhere offers for the use of man, and which is so frequently suffered to run to waste. Neither "F.I.R.S." nor Sir William Thomson has as yet furnished us with even an approximate estimate of the cost of maintaining a Faure's battery as measured by the amount, of force which it is capable of exerting; and it must not be forgotten that a million foot pounds, although sounding like an enormous amount to those who are unfamiliar with the form of expression, is yet something which would not go very far in the way of supplying the motor wants of a workshop. Faure's battery is constructed mainly of lead—a circumstance which necessarily renders it heavy, and in a corresponding degree costly of carriage; while a new demand for the metal, if in large quantities, must, of course, tend to a considerable enhancement of its price. Against these considerations must be set the obvious one that other materials may be found capable of employment in a similar manner; the principle of the battery being that the electricity with which it is said to be charged is expended within it in the production of chemical change, and is released again by the establishment of a new action by which the materials employed are suffered to return to their original condition. There is no primá faci≖ reason why lead should be more available for this kind of composition and decomposition than some other substances; and now, that the method of producing the desired effect has been made known in the case of lead, philosophers will soon be engaged in the endeavour to discover some substance which may offer still greater advantages for the purpose. Unless the price of storage should be found to offer practically insurmountable difficulties, there can be no doubt that the new discovery will hasten, by many years, the general application of electricity to industrial and domestic purposes.

To those who remember the solicitude which was expressed, not many years ago, about the gradual exhaustion of the English coal field, and about the inevitable loss, whenever that exhaustion reached the point of famine, of English maritime and manufacturing page 5 supremacy, it will be curious to think of a possible near future, in which the "black diamonds," so highly prized by our forefathers and by ourselves, may have passed quite out of the range of practical application; and may possess none but an historical interest, as the sources of our mechanical power when we did not know how to obtain it in a better way. We believe it was Sir William Thomson himself who once spoke of Niagara as the natural and proper chief motor for the whole of the North American Continent; and it now seems quite within the bounds of possibility that persons who are now living may witness the application of this chief motor to the indicated uses. It is possible that they may see electricity brought by electric railways from the coasts, or from the estuaries of tidal rivers, and delivered in the great towns for the fulfilment of all the purposes for which coal is at present either directly or indirectly employed; and it would not be easy to exaggerate the benefits, from many points of view, which such a substitution of electricity for coal would afford. If we can imagine the atmosphere of London smokeless and clean, uncontaminated either by the solid or by the gaseous products of combustion; with flowers and fruit flourishing in town gardens; with our rooms, and especially our public rooms and places of assembly, freed from the heat which gas occasions; and with nature and art manifest in their true colours by night as well as by day; our pictures uninjured, our precious metals uncorroded; and, indeed, with many of the chief features of unwholesomeness which now arise from the aggregation of masses of people so much alleviated as to be scarcely perceptible, we shall be able to form some estimate of the advantages which the displacement of coal, its congeners and its products, by electricity, would be not only likely, but sure to accomplish. Such is the future which can be foreshadowed with some certainty for our descendants, even if not for ourselves; and a great step in the direction of its being brought about, a great step towards lifting it from the region of mere hypothesis into that of high probability, was taken when the little box, with its stored million of foot pounds of electric energy, was conveyed by our correspondent from Paris to Glasgow.—Home Paper.