[ 3^5 } 



Hence we fee, lo. That when the temperature of the air is 

 from y^° to 80°, and during a calm, the cold produced in 

 water in five minutes is from 8*^ to 12^, even though the 

 rays of the fun be intercepted : 



2dly, That during the gentleft breeze from the fouth the cold 

 is diminifhed, but if from the north or eafl, it is increafed : 



3dly, That where the temperature is from 65° to 75'', the cold 

 produced is from 5^ to 8° : 



4thly, In temperatures from 53"^ to 65°, the cold produced is 

 from 3^ to 5^ : 



5thly, It is plain that the cold produced is proportioned to the 

 quantity of evaporation in a given time ; when this quantity is 

 very fmall, as twelve grains per hour, or one grain in f:ve minutes, 

 as in temperature 50°, in fuch circumftances the cold produced 

 is fcarcely perceptible ; but if the water be expofed to a current 

 of air, and this air' unfaturatcd, the cold may be more confi- 

 derable. 



Sai'^si'RE, as ufual, made feveral ingenious experiments on the 



cold produced by evaporation in agitated air, both on a mountain 



Vol. Vill. S s where 



