272 ESSAY 



EXPERIMENT 1st. 



With a view to imitate the method of making 

 ice described by Sir R. Barker, I had a pit dug, 

 on the evening of the 3rd of May, in the middle 

 of the garden so often spoken of, 4^ feet long, 

 3 wide and 2 deep. It consequently had the 

 same depth as the excavations mentioned by 

 that gentleman, but was considerably less in its 

 other dimensions. Clean dry straw was then 

 strewed, to the height of a foot, over the bottom 

 of the pit. On the straw were next laid a num- 

 ber of small shallow earthen pans, a part of 

 which were glazed, and a part unglazed. In 

 the last place ; all the pans were filled with soft 

 water, which had been boiled on the same even- 

 ing. Contrary to my expectation, the unglazed 

 pans remained as dry on the outside, after water 

 had been poured into them, as those which were 

 glazed. I conclude, therefore, that the former 

 were more dense in their substance, than the 

 unglazed pans used in India; and that their 

 density was probably the reason, why ice did 

 not afterwards form in them, sooner than in 

 the glazed pans, which were employed by me. 



Two pans, containing boiled water, were set 

 upon the grassplat, at a little distance from the 

 pit. A watch-glass filled with boiled water was 



