88 Means of making Ice by the Natives of Bengal. (Fes. 
towards daybreak to the S. W. direction, when the air was mild and 
moist, and ice had formed on very few of the dishes placed upon the 
straw. Soon after sun-rise a mist appeared over the ice-beds. The 
air was at 53.5°, and the temperature of the straw 42°. The tempera- 
ture of the water, which in one of the common unglazed dishes in the 
evening was 56°; in a black glazed one was 58°; ina white glazed one, 
59°; in the morning the temperature of the water in one of the common 
unglazed dishes, with a film of ice on its surface, was at 34°, in the 
dish next it without ice 35°. The water in a white saucer had a thin 
sheet of ice upon its surface and was 35°, and in a deep white cup, 
without ice 39.5°, ina black glazed cup 36°, in a deep one of the same 
material 38°, and in a flat glazed plate 36°. On another morning of 
the same kind, a black coloured copper vessel had no ice, while a white 
painted brass vessel was covered with it. 
The influence of brass dishes in conveying away the heat was made 
evident by the ice being thicker than on the other dishes, and extend- 
ing from the under edge of the plate of ice upon the surface of the 
water for some distance along the inner surface of the brass dish. 
(February 2.) The ice was thick, and numerous small triangles were 
found a little to one side of its centre, which were not completely closed 
at their apices, and around this central point the ice was bulged out and 
thin, and, on examining its under surface, numerous crystals were found 
to have formed at the raised part where the ice was thinner ; from whence 
they shot obliquely towards the centre of the water, underneath the 
upper plate of ice, where a small aperture was situated. 
On the 2nd and 3rd of January, (1832,) there was only a thin film 
of slightly irregular ice on the surface of the brass dishes without any 
appearance of ice upon the water, in most of the plates, which with 
the exposed portions of straw, grass, &c. were moist. The water in 
the dishes which had not frozen near the sides of the beds, stood at 
from 32° to 33°. In a dish put upon another with water in it the upper 
stood at 32°, and the under at 33°. From these experiments the water 
appears to be influenced by its depth, exposure, and the materials and 
colour of the dishes employed for making ice. 
In Bengal the day is always hot, and the tendency of caloric to ar- 
rive at a state of equilibrium would soon render bodies on the surface 
of the earth of the same temperature, were it not that each has an apti- 
tude to receive and a power to discharge caloric, which is influenced 
principally by the nature of the surface of the body and its temperature. 
The degree of heat will vary with the power of the body, which may, 
however, be influenced by the evaporation from it by winds and air 
