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The flate of the inftruments, before the experiment began, 

 was as follows: hygrometer LXXII. interrnediate' thermometer 

 62"^, upper thermometer 61,5, lateral thermometers,.^ach 62°. 



The experiment began eight minutes before two o'clock, and 

 at eight minutes after two I found the ftate of the inftruments as 

 follows : the intermediate thermometer ftill at 62", the upper at 

 61^, and the lateral ones both at 61°. The hygrometer was un- 

 fortunately broken during the experiment. 



The fquare piece of linen, in the mean time, (that is during thofe 



fixteen minutes) loft 23,25 grains of its weight; each fide of it 



therefore loft 11,625 grains. The dimenfions of each fide of the 



fheets were 8,5 feet in length, and 6,5 in breadth =35,25 fquare feet ; 



hence each fide of each fheet fhould lofe 1 1,625 grains x 3 5125=409,78 



grains. But it is plain from the unvaried ftate of the intermediate 



thermometer, that the evaporation from the internal fides was ob- 



ftruded, that from each being obftruded by that from the op- 



pofite fide ; and as the upper thermometer was lowered only half 



a degree .while the lateral thermometers v^^ere lowered each one 



degree, it follows that each of the internal fides evaporated only 



one-fourth as much as one of the external fides, and both 



together half the quantity evaporated by each of the external 



fides. 



The 



