ON DEW, &c. 271 



3. The cold, by means of which ice is pro- 

 duced in Bengal, appears, as I think may be 

 inferred from what is said by Sir R. Barker, in 

 its greatest degree, like cold from radiation 

 in other substances, on those still and serene 

 nights, during which little dew is deposited by 

 the atmosphere. 



4. Clouds and wind prevent the formation of 

 ice in Bengal ; and the same states of the atmo- 

 sphere either prevent, or considerably diminish, 

 the occurrence of cold from the radiation of 

 heat at night by bodies on the ground. 



I shall close this subject, by giving some ac- 

 count of a few attempts to procure the freezing 

 of water at night, in this country, by exposing 

 it to air of a temperature, higher than that of 

 32. These were made by me in 1812, at my 

 usual place of experiment, which was formerly 

 stated to be not well adapted for the appearance 

 of a great cold from radiation, and on nights 

 not among the most favourable to such an un- 

 dertaking, even of those which occur in this 

 country. It is proper also to mention, that I 

 was then less able to conduct such experiments, 

 and to make use of them, than I afterwards be- 

 came, from a longer attention to similar objects. 



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