262 ESSAY 



which are the calmest and most serene, and on 

 which very little dew appears after midnight ; 

 that clouds and frequent changes of wind, are 

 certain preventives of its formation; and that, 

 although ice is thus very readily procured by 

 art in Bengal, during the winter, it scarcely 

 ever occurs there naturally. 



The process described by Mr. Williams must, 

 from its extent, 300 persons being employed in 

 it, have been carried on for profit, and would, 

 consequently, be conducted in the most eco- 

 nomical manner. A piece of ground, nearly 

 level, containing about 4 acres, was divided 

 into square plats, from 4 to 5 feet wide, which 

 were surrounded by little mounds of earth, 4 

 inches high. In these inclosures, previously 

 filled with dry straw, or sugar-cane haum, were 

 placed as many broad, shallow, unglazed earthen 

 pans, containing unboiled pump water, as they 

 could hold. The air was generally very still, 

 when much ice was formed ; wind prevented 

 its formation altogether. In the morning, be- 

 tween 5 and 6 h., at which time alone, Mr. Wil- 

 liams made his observations, a thermometer, 

 with its bulb naked, placed on the straw, amidst 

 the freezing vessels, was never found by him 

 lower than 35 ; and he has observed ice, when 

 a thermometer so placed was 42. Another ther^ 

 mometer, suspended 5j feet above the ground, 



