ALEXANDER MACFARLANE—RAINMAKING. 
77 
charged with such explosives as nitro-glycerine, dynamite, gun cotton, 
gun powder, or fulminates, and connecting the balloon with an electrical 
apparatus for exploding the cartridges.” 
Suppose that we have a mass of supersaturated air in the atmosphere, 
no nuclei being present on which the moisture can condense; Aitken’s 
experiments lead us to believe that the mechanical shock due to an ex¬ 
plosion inside or near the mass of air would cause the excess of moisture 
to condense. But suppose that a cloud has already formed; that fact 
means that condensation has already started, and that there is no want 
of nuclei. When the excess of moisture has already condensed, we have 
no reason for believing that a shock such as that intended by Mr. Rug- 
gles would cause more moisture to condense; for the temperature of the 
air must first be reduced, and the direct effect of the explosion is to ele¬ 
vate, not lower the temperature. 
5. Dyrenforth .—As the result of the agitation of Mr. Powers, Con¬ 
gress voted $2000 to make a preliminary test, and the inquiry fell to the 
scientists of the Department of Agriculture. They reported that there 
was no foundation for the opinion that days of battle were followed by 
rain, any more than days of no battle. It was then that Mr. Dyrenforth 
came forward with Ruggles’ plans and offered to make some tests. An 
additional appropriation of $7000 was placed at his disposal for a series 
of practical tests, which were made at Midland, Texas, in August of 
1891. A further government appropriation was expended in tests at San 
Antonio in November of this year. 
So little does Dyrenforth understand the nature of the problem, that 
his plan of operations is as much as possible an imitation of a battle. The 
ground explosives were fired off in a line facing the advancing clouds; 
the chloride of potash supplies the place of the smoke from the gun pow¬ 
der; shells are projected into the air at frequent intervals; the general 
and his lieutenant even wore cavalry boots. Instead of using a balloon 
to carry up solid explosives and touching them off when aloft by an 
electric current, he used cheap balloons filled with hydrogen and oxygen 
in the proportion required for forming water, and the combination was 
started by a time fuse attached to the balloon itself. He changed from 
an explosive to an implosive agent, without apparently being aware of 
any difference. But there is an important difference. The heat of com¬ 
bination of the oxygen and hydrogen is increased by the falling in of 
the atmosphere into the empty space produced; while the heat of combi¬ 
nation of a solid or liquid changed to a gas is diminished by the cooling 
of the gas in expanding. 
The largest balloon used had a content of nearly 1000 cubic feet. The 
combination of the hydrogen and oxygen produced as‘much heat as 
would raise 1300 pounds of water from the freezing point to the boil- 
