242 QUEENSLAND AGRICULTURAL JOURNAL. [1 Aua., 1901. 
were made in Styria, and were based on a deeply rooted popular custom. For 
centuries it has been the custom in that country of vineyards and orchards, 
when a threatening bank of clouds appears on the western horizon, to fire blank 
shots from a certain kind of mortar, and it was always remarked, or people 
thought they remarked, that instead of the hail expected, nothing fell but a 
violent shower of rain, that seemed to increase in intensity after every shot, 
just as. can be observed after every flash of lightning. Of late years Herr 
Stiger, the mayor of Windish-Feistritz, in Lower Styria, has begun to ‘ shoot 
the weather’ on a large scale, more systematically, and consequently with more: 
success. Within the short space of four years not only have large parts of 
Styria, Lower Austria, Hungary, the Tyrol, and the whole of Upper and) 
Central Italy been supplied with thousands of such shooting stations, but 
it has had the further advantage, that men of science have now begun to be: 
interested in the matter. In November of the year 1899, there was held the 
first ‘‘ weather shooting” congress in Casale Monferrato, which was attended. 
by 560 practicians and scientists. The following resolution was there agreed 
to :—‘* The facts here observed have proved the benefit of firing into the air, and 
therefore, in face of these facts, it is immaterial whether men of science are 
able to explain it or not.” For, as it has hitherto been impossible to form an 
undisputed theory as to the formation of hail, so there is also no incontro-. 
vertible explanation of the effects of firing into the air. There are, however, 
doubtless two factors that have to be considered—namely, the vibration of 
sound and the whirlwind of air caused by the shot. There are no physical 
grounds for believing that the waves of sound, as such, can in any way prevent 
the formation of hail. Were it argued that the waves of sound could produce 
a shock in the lower clouds, and thus suddenly prevent the formation of hail, it 
would doubtless be objected that wave-sounds cannot produce a shock in the 
air, but only an oscillation. ; 
This shock could, however, be produced by the whirling of the air caused 
by shooting on the Stiger system. As early as 1896, Stiger tried to increase: 
the effect of the explosion by attaching large funnels to the mortars ; it then 
appeared that on firing a shot, rings of whirling air—similar to rings of smoke 
—would rise from the funnel, and were visible in the reflected light of the ‘sun. 
These whirling rings of air are formed by the air in the funnel being set in a 
whirling motion by the explosion of the powder. The sound made by the 
sudden rising of the whirlwinds of air can, at night-time, or when the wind is 
still, be heard at twenty miles’ distance. From the very beginning this noise: 
was, for Stiger, the gauge by which to measure the effectiveness of the shot, 
and haying once observed that a swallow, caught by such a whirlwind of air, 
fell down, he henceforth considered the mechanical force of the ring of air as 
the power that disturbed the formation of hail. 
It now became evident that it was necessary to produce strong atmospheric 
whirlwinds starting with greater rapidity and lasting longer. Special machines 
were built for this purpose, and have now not the least resemblance with a 
mortar. Our illustration affords an idea of what these new “ hail-destroyers,” 
or “cloud cannons,” look like ; it represents a visit paid by the King of Italy 
to one of these shooting stations fitted out with the improved machines. ‘The 
place where this experiment was made expressly for the king was an improvised 
shooting-station outside the St. Lorenzo Gate in Rome. Both on his arrival 
and on his departure the king was greeted by a regular salute from these air-. 
cannons. 
For several years past a similar apparatus as that represented in this 
picture was employed in Styria. A. scientific investigation into the causes of the 
effect produced was made last year by the Viennese meteorologists, Permer and. 
Trabert, at the desire of the Austrian Minister of Agriculture. They found 
the mechanic energy of the rings of air to be very considerable. The 
greatest effect attained in a horizontal direction was the breaking of 
lathes of firewood 3 metres long, 6 em. broad, and 4 em. thick, which were set 
up at a distance of 40, 60, 80, and even 100 metres from the cannon. More: 
