TRANSLATIONS AND SELECTED ARTICLES. 39° 
time to enter, but the lighter vertical portions are alone or princi- 
pally absorbed. Only in this case is the cold sufficient to form ice. 
In the hail-cloud we may assume a funnel-shaped vortex (strudel) of 
ice-cold air, with frozen and liquid water, which descends spirally 
towards the earth. If this be true, a hail-storm should only be of 
limited extent, which is well known to be the fact. When the con-" 
densation takes place over a large area, the latent heat of the con- 
densing vapour is sufficient to prevent the formation of ice, and an 
ordinary rain storm results, hail is only formed when the colder air. 
is rapidly drawn into a narrow space. 
According to this theory a hail-storm cannot stand still, or con-: 
tinue over one spot for any length of time; it must stop when the 
lower strata are cooled. -But as it progresses in any direction it 
meets with fresh materials for its reproduction. If we imagine a 
hail-funnel moving onward, its path will be in the shape of a long 
narrow cleft in the atmosphere, and it is easy to conceive how the 
force of the hail-storm may continue the same or may even increase, 
as was the case with the notorious hail-shower which passed through: 
France and Holland in 1788. 
Hail belongs essentially to temperate climates, it is not observed 
in the tropics or in high northern latitudes. In the latter the air. 
is cold and dry, no considerable vacuum can be formed, and hence no 
sudden entry of cold air. The most severe hail-storms occur in 
Sicily, the south of France, and the coasts of the Mediterranean. 
(Very enormous single hail-stones have also been observed in the 
middle States of the Union.) In the tropics the lower strata of air 
are so hot that when a commingling of two masses takes place, the 
latent heat of the condensing vapour is so great as to prevent the 
formation of ice, and even to cause the descending rain to possess @ 
remarkably high temperature. 
Hail is observed more frequently after mid-day than before, 
oftener by day than by night, because the lower atmosphere is then, 
warmer and moister. 
According to this theory we should imagine that windy weather 
would be unfavourable to the formation of hail, and that any dis-, 
turbance occurring on still sultry weather would tend to its forma- 
tion. This is found to be the case. . 
Hail indicates a storm or tempest, (Gewitter,) but a storm need 
not be accompanied by hail, the latter is only a phase of the phe-. 
