National Geographic : 1894 Apr 25
Gathmnan's Plan. In making some experiments last year, a shell filled with liquefied car bonic acid gas was exploded at a height of 600 feet; a cloud was produced in the clear sky at once, and, floating along on a current of air, was visible for miles. This experiment was made in July, 1890, and since that time I have made sufficient other experiments to satisfy myself that I can pro duce rain whenever necessary, or at will. Experiments made in my astronomical observatory, at a height of only seventy-five feet, have proven that by the evaporation of liquefied carbonic acid gas a rain shower on a small scale can be produced with but a small quantity of the gas. When completed arrangements have been made, the experiments mentioned will be seen to be but a step to the practical illustration on a grand scale. It appears that in Gathman's method the explosion plays a very subordinate part; but in the method to follow the explo sion is the main, if not the only thing. Fourth Method.-The concussion theory is probably an old one, though it is not correct to refer it to Plutarch, as is sometimes done. In his life of Marius, referring to the battle with the Teutons near Aix, in July, 102 R. C., Plutarch says: " Extra ordinary rains pretty generally fall after great battles; whether it be that some divine power thus washes and cleanses the pol luted earth with showers from above, or that moist and heavy evaporations steaming forth from the blood and corruption thicken the air, which naturally is subject to alteration from the smallest causes."* Here are two distinct suggestions for rain making, but not that of concussion. The first elaborate treatment of the concussion theory appears to have been by Edward Powers, civil engineer, who published in 1890 a book on the relations of battles to rainfall, The first edition was printed in Chicago in 1871, but most of the edition was destroyed by the great fire in that city, which also destroyed the stereotype plates. The latest issue seen by me contains an inset of 15 pages devoted to a criticism of Professor Newcomb's article already mentioned. The aim of this book is to prove that great battles or heavy cannonading are usually soon fol lowed by rainfall. A fair criticism of the book is that such phenomena are not invariably followed by rain. The coinci dences could be explained by the fact that in the season of mili *Plutarch's Lives, Clough's revision, Am. Book Exchange edition, 1881, pp. 390-391.
1894 May 23
1894 Mar 17