244: QUEENSLAND AGRICULTURAL JOURNAL. [1 Ave., 1901. 
some 30 feet in length. The mortar is journalled in a rotatable carriage, so that ~_ 
it can be raised and lowered and swung from side to side. The charge is a 
metallic cartridge of blasting powder. After the discharge a loud, shrill 
whistling sound is heard, lasting for about fourteen or fifteen seconds.-~, 
French and Ttalian winegrowers insist that, by means of the gun, clouds 
are torn asunder, so that rain instead of hail falls. 
The grapegrowers of five departments of the French Alps have'formed an . 
association for buying cannon and powder for next summer (1901). The Italian 
Government has such faith in weather-shooting. that it supplies winegrowers 
with powder at the rate of 3 cents (14d.) per lb.—Scientific American. 
HAIL PREVENTION. 
In all the articles we have read on the subject of “ weather-shooting,” we 
note that stress is always laid, not upon rain producing but upon hail 
prevention. The fact that the hail is turned into rain does not prove that rain- 
clouds could be induced to deliver their moisture by means of air waves. It is 
hail that is the enemy to be fought. And this opens up the interestin 
eon of the mechanical action of the air waves produced by the shock o 
ischarge. Our own experience has shown that when the big guns at Lytton 
fort have been fired during very cloudy weather no rain fell. The guns, how- 
ever, were not laid for high-angle fire. 
