a Mifcellanea Curiofa. 



Real and Philofophical Meteorology, and, as fuch ; 

 to defer ve the Consideration of this Honourable 

 Society. I thought it might not be unacceptable 

 to attempt by Experiment to determine the Quan- 

 tity of the Evaporations of Water, as far as they 

 arife from Heat, which upon Trial fucceeded as 

 follows. 



We took a Pan of Water, adout 4 Inches 

 deep, and 7 Inches T % D'a meter, in which we 

 placed a Thermometer, and by means of a Pan 

 of Coals, we brought the Water to the fame de- 

 gree of Hear, which is oblerved to be that of the 

 Air in our hotteft Summer; the Thermometer 

 nicely (hewing it : This done, we affixed the 

 Pan of Water, with the Thermometer in it, to 

 one end of the Beam of a Pair of Scales, and ex- 

 actly counterpois'd it with weights in the other 

 Scale ; and by the application or removal of the 

 Pan of Coals, we found it very eafie to main- 

 tain the Water in the fame degree of Heat pre- 

 cifely. Doing thus we found the weight of the 

 Water fenfibly to decreafe ; and at the end of two 

 hours we oblerved that there wanted half an 

 Ounce Troy j all but 7 grains, or 233 grains of 

 Water, which in that time had gone oft' in Va- 

 pour \ tho' one could hardly perceive it fmoke, 

 and the Water were not fenfibly warm. This 

 Quantity in fb fhort a time feenyd very confide- 

 rable, being little lefs than 6 ounces in 24 hours, 

 from fo fmall a Surface as a Circle of 8 Inches 

 Diameter. To reduce this Experiment to an ex- 

 act Calculus, and determine the thicknefs of the 

 Skin of Water that had fb evaporated, I affume 

 the Experiment aliedg'd by Dr. Edward Bernard to 

 have been made in the Oxford Society, vi%. That 

 the Cube- foot Engliftooi Water weighs exa&ly 76 



Pounds 



