104 
of that air to the dew-point would require the abstraction of as much heat 
as would raise 88,000 tons of water from the freezing to the boiling point. 
3 ; h 
spread over a square mile would give about 1.4 pounds per square foot, or 
0.7 of an inch of rainfall. The amount of latent heat set free by the con- 
densation of that amount of water would raise 100,000 tons of water from 
the freezing to the boiling point, and it tar be necessary to abstract this 
heat in order that the rainmaking might go on. The foregoing on the pre- 
sumption that the cubic mile of air be ced: constant; if the air operated on 
is cy eager changing the task becomes one of infinitely greater difficulty. 
The sp that battles occasion rain is older than the invention of gunpow- 
wah for Plutarch in a sentence often quoted, says: ‘‘It is a matter of cur- 
rent observation that carat area rains pretty generally fall after we 
tice ” And he explains this by supposing that some divine 
this way cleanses the earth or that the vapor from the blood steams va 
and makes moisture fall. If from a great heat a large body of air is made 
to ascend in a column a large cloud will be generated and that cloud will 
_ Contain in itself a self-sustaining power, which may move from the-place 
_ over which it has formed and cause the air over which it passes to rise up 
into it and thus form cloud and rain, until the rain may become more gen- 
eral. This isin theory, but the records of great fires do not show that rain 
ould produce rainfall. The Texas experiments were made without at- 
Geaine to produce rain when the conditions were favorable for rain, but 
under any and all conditions the attempt was made, with the result a prac- 
tical failure, though in a few instances a few drops of rain fell 
It may be stated in conclusion that, admitting that explosives and fires 
have in some few cases determined rainfall, they can only do so when mois- 
ture is present in sufficient quantity in the air, and when the other condi- 
tions, such as temperature and wind, are favorable. In other words, when 
_ the conditions are — et for rain, explosives and fires may precipitate 
rain, but when the air is too dry, no artificial means can cause rain to fall. 
Legitimate scientific siiedileabae for the production of rain should be en- 
couraged, but the experiments should first be carried on in the physical 
laboratory before attempting them upon natures great physical laboratory. 
Those people who do not desire to be duped will do well not to contract or 
subscribe for any rainmaking agents for the production of rain. Money in- 
_ Vested in developing yowepene canals 8 prove to be of far greater value 
and yield ten thousand fold more return 
Weather Bureau Office, San nies: Cal., April 11, 1894. 
