The New Zealand Railways Magazine, Volume 14, Issue 4 (July 1, 1939)
Rain-Makers at Work — Experiments in North Otago in 1891
It would be safe to say that there has been no man in the world's history who has not, at some time or other, longed to command the elements and to conjure from the skies sunshine or rain at will. Yet the weather has remained the one great condition of life beyond human control, and we continue to accept as cheerfully as possible whatever the heavens may send. It is interesting then to learn of at least one attempt to modify this attitude of tame passivity—an attempt made in our own country nearly fifty years ago.
The North Otago district has a climate with a rainfall considerably below the Dominion average, the mean annual precipitation over a long term of years being about 22 inches. Pleasant as such conditions are from a residential point of view, occasional periods of more extreme aridity cause concern to farmers. This was notably the case in the years 1889 to 1891 when drought seemed to have seized the land in a permanent grip. In both 1889 and 1890 only 14 inches of rain fell, and in the eight months, from March to October of the following year, the gauge at Oamaru recorded no more than 6.64 inches. After the failure of two seasons’ crops the agriculturist faced, with a heavy heart, the prospect of a third dry summer.
Although many were suspicious of any report that came out of America, page 15 the sponsorship of the United States Government lent these accounts an air of authenticity, and it was widely felt in North Otago that similar experiments might at least be worth trying in that area of the province. On 14th November, 1891, therefore, a meeting was convened in Oamaru of farmers and others who might be interested in discussing the suggestion. The Mayor of Oamaru, Mr. D. Dunn, presided, and there was a large attendance. While speakers were cautious in expressing any faith in the success of the scheme, it was generally agreed that a trial should be made, and a committee was set up to direct operations. Arrangements were also made to canvass the district for funds, and a considerable sum was subscribed in the room.
In the meantime, however, the threat to his prestige contained in these proceedings apparently stimulated to activity the controller of the celestial water-taps, for, by an amusing coincidence, on the day after the meeting heavy rain fell and continued at intervals during the following week. But the committee did not abandon its campaign on this account. The Government was approached and gave its official blessing to the project by a promise to subsidise the money raised locally, to supply guncotton at cost price, and to place the services of members of the Torpedo Corps at the disposal of the committee.
By 27th November the preparations were completed and the members of the committee with their expert advisers proceeded to Raki's Table, an eminence of 1,020 feet situated about 15 miles inland. It was found, however, that conditions were unfavourable: a strong nor'-wester was blowing, and a difference of four degrees between the wet and dry bulb thermometers indicated a lack of humidity in the atmosphere. Nevertheless, it was decided to make a trial to gain evidence of the quantities of explosives required. In this experiment 15 lbs. of dynamite and 10 lbs. of guncotton were fired, and some singular results or accompaniments were noted. A ring of cloud formed overhead and the wind immediately calmed. The sound of the explosion was distinctly heard in Oamaru. Whether or not by coincidence, rain fell that night and continued during the next day.
The explosion had other results. At Ngapara, four miles away, the face of a gravel pit began to move and several tons of earth and gravel fell, a child having a narrow escape from being overwhelmed. Another effect was that on a perch, at a similar distance, a row of roosters was hurled to the ground by the force of the explosion.
A third and final experiment was made on 4th December under conditions page 16 distinctly unfavourable to the production of rain by natural means. At 5 p.m. the barometer read 29.49 and was rising steadily while the wet and dry bulb thermometers indicated an atmosphere 8 degrees from saturation. A brisk south-east breeze was blowing. At 6.3 p.m. 60 lbs. of dynamite, 12 of gunpowder, and 3 of guncotton were exploded. Shortly after, the barometer fell to 29.47, the wet and dry bulbs read 57 and 61 degrees respectively, and the wind calmed. Clouds gathered and a few drops of rain fell. At 7 p.m. the thermometers were equal at 54.2 degrees, but this indication of saturation was attributed to the falling dew. At 7.30 the clouds had a distinctly watery appearance and the experimenters prepared confidently to put the scheme to the final test. At 8 p.m. 100 lbs. of dynamite, 28 of gunpowder, and 6 of guncotton were set off. producing perhaps the greatest sound ever heard in the district. The results were disappointing. The wet bulb thermometer fell one degree, indicating a drier atmosphere, and although the barometer continued to fall slightly, no rain came. At 9 o'clock a third shot-was fired but without result beyond disturbances in the atmosphere shown by the agitation of the smoke from the powder, and with this the attempts were abandoned.
It will be noted that balloons were not used, attempts made to construct them failing on account of the difficulty, in view of the limitations of time and finance, of securing suitable material. All the explosions were fired from a derrick 30 feet high.
The committee's final report contained the following conclusions: “The atmospheric disturbance was so marked upon all three occasions in accumulating rain clouds that we believe that there is far more in the practicability of the scheme than anyone is aware of, for, though somewhat sceptical at the outset, we were made easy converts as to the possible results, and, although these few experiments were far too limited to build a theory upon, the results possibly being coincidences, they certainly offer great inducements for more lengthened trials, and we offer our conviction for what it may be worth that passing moisture-laden clouds may be intercepted and caused to part with their moisture by an explosion, and if our conviction becomes an established fact, there is nothing to prevent this district from becoming one of the most prolific in the colony. In handing in the account of our stewardship we certainly think that the matter should not be allowed to drop here, but are of opinion that in a somewhat inexpensive way a station could be erected on a high central point supplied with the best of instruments for taking careful readings (which can hardly be done with the temporary instruments carried about), having a mine laid on or a balloon to liberate, to use them when favourable circumstances occurred, and this continued for a time would soon let us all know whether the scheme was really practicable.”
No further steps were taken, however. Interest had waned with the breaking of the drought; public opinion tended to be sceptical and even derisive, attributing the successes claimed by the committee to mere chance. The present writer is not competent to give any opinion on the scientific aspects of the scheme, and here merely records the details of an experiment which aroused considerable curiosity at the time, both in North Otago and throughout New Zealand.