240 PREVESTIOX OF HAILSTORMS BY USE OF CANNON 



Casale Monferato. At this congress the minister of agriculture was 

 represented by the under secretary of state, and the ministries of war 

 and the interior also sent delegates. Five hundred participants in the 

 congress appeared, some of them the most distinguished scientists of 

 Italy. Mr Stiger was elected honorar}^ president, and a committee of 

 four eminent professors, representing Styria, Piedmont, and Venice, 

 were appointed to report on the results of the Stiger method for ])re- 

 venting damage from hail. The committee unanimously agreed that 

 "if the shooting was commenced in tihie the damage from the hail 

 was always averted." A number of instances were cited showing that 

 in the towns where there was no shooting the destructive violence of 

 the hail continued unabated, whereas in the districts where the shoot- 

 ing was done no hail occurred. 



Mr Stiger, the inventor, however, particularly warns the public 

 against being oversanguine, as he asserts that, in sjaite of the many 

 successful results obtained by his process, there is not yet the cer- 

 tainty of its effectiveness. 



Every one is naturall}' asking the question, How can the formation 

 of hail be influenced by "weather firing"? I confess that I am not 

 able to answer, but I must assert that because we cannot comprehend 

 the process we have not the right to deny its existence. In explain- 

 ing the action of the cannon, two points are to be considered — the 

 effect of the explosion and the force of the vortex ring that rises from 

 the gun barrel. In the sultry, distressing calm that })recedes violent 

 storms it is almost a natural necessity to make a noise, and as loud a 

 noise as possible. One feels that from the sultry calm before the 

 storm misfortune is to come, and that b\' disturbing the stillness the 

 misfortune may be turned away. Mr Stiger states that he was guided 

 by this thought when he began his experiments in 1886. " The ob- 

 servation," he says, "that everv hailstorm is preceded by an abso- 

 lute stillness of the air, accompanied by heavy oppression, suggested 

 to me the idea of disturbing this calm which seemed essential to the 

 formation of hail, and therefore I tried 'weather shooting,' which 

 has been known for centuries." 



That vibrations can destroy the formation of hail has no founda- 

 tion in physics. As far as our knowledge reaches, for we do not yet 

 understand the hail-forming process, the explosion could not affect 

 the process, either through changes in the clouds, or by the prema- 

 ture freezing of droplets through concussion, or through a consider- 

 able concussion. 



