32 Proceeditigs of the Newport Natural History Society. 
from the ground in advance of the storm being carried 
into the cloud-mass where it serves as a.nucleus for the 
condensation of the rain or snow. 
Except in its accompaniment of large hailstones the 
storm did not differ essentially from other similar tornadoes. 
The unusual size of the stones was unquestionably owing 
to the convectional currents of the storm area, which carried 
them up and down many times before they fell.* In all 
storms of this class the rain drops in the cloud are carried 
upward, from the low levels where they are formed, by the 
central ascending currents, to a height where the tempera¬ 
ture is very low, and where they are converted into snow 
or ice pellets. These are then swept down by the descend¬ 
ing currents near the margin of the storm, particularly at 
the front margin, and are increased in size by the deposi¬ 
tion of a layer of damp snow, which is afterwards frozen 
harder. When the hailstones make this circuit of the storm 
cloud but two or three times they are not of large size. 
But it sometimes happens that when the convectional cur¬ 
rents are very powerful the stones are repeatedly carried 
inward at the base of the cloud, upward through its centre, 
and down the outer margin, receiving with each rotation 
additional layers of ice. In the storm of last July the cur¬ 
rents must have been of unusual strength, carrying the 
stones up and down the cloud-mass, until, the ice balls 
became too heavy for further carriage and fell into the 
region of the squall. 
The thunder squall is, as is well known, a violent out- 
rush of cool wind, at the base and in front of the storm, 
under the rising inflow of the warm surface wind. It occurs 
immediately before the storm breaks, and though limited 
in extent its violence is excessive, as is shown by the damage 
it does to trees and the comparatively heavy objects which 
it sweeps into the air along with the lighter dust of the 
roads. The remarkable velocity of the squall in this storm 
will account for the almost horizontal direction of the hail¬ 
stones. They were swept along in the same manner as 
