1833.] Means of making Ice by the Natives of Bengal. 83 
Repeated trials have been made at different times to accomplish the 
desirable object of keeping the ice during the hot season; but so 
great is the first expense, and so smalla quantity of that produced yields 
any return, that hitherto every trial has proved unsuccessful, and has 
entailed a heavy loss on the speculator. For the two last seasons, ano- 
ther attempt has been made to keep ice, but although every precaution 
was employed to guard against the influence of the surrounding media, 
so powerful was it found during the last season, when the trial was for 
the first time properly made, that the experiment proved unfavourable, 
or only partially succeeded. The ultimate success of the measure must 
now however depend in a great measure on the encouragement it re- 
ceives in Calcutta, through which the best hopes may be held out of 
introducing one of the greatest luxuries in a tropical climate during the 
hot-season. 
When the ice bed is examined after a favourable night, the straw ex- 
posed between the plates and their sides is found covered with hoar- 
frost, and near the water on the inner side small irregular nodules of 
ice appear. 
When the night has been very favourable, so as to freeze a consider- 
able portion of the water, numerous small globules of air, naturally 
combined with water, are disengaged during the freezing process, and 
are found swimming upon the surface of the water, while others remain 
attached to the bottom of the plate. 
The separation of air from the water increases as the congelation 
advances, and retards its progress more and more, as the proportion of 
ice is greater, until nearly all the water is congealed, when a large glo- 
bule of air is left at the lower and central part of the ice. 
_ By expelling the air naturally contained in the water, by boiling, an 
increased quantity of ice is produced, but the expence of doing so is 
too great to admit of its being generally employed. On an evening in 
the cold season, I boiled some water for a short time, and found next 
morning more ice, but apparently as much air as in the neighbouring 
dishes. 
When the wind attains a southerly or easterly direction, no ice is 
formed, from its not being sufficiently dry, not even, though the tem- 
perature of the air be lower than when it is made with the wind from a 
northern or western point. The most favourable direction of wind for 
making ice is the N. N. W. diminishing in power as it approaches the 
north and west: im the latter case, more latitude is allowed than from 
the N. N. W. to the north. So great is the influence of the direction of 
the wind on the ice, that when it sometimes changes in the course of a 
night from the N,N. W. to a less favourable direction, the change not 
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