C 361 3 



XXI. jin Account of fome 'Experiments on the Lofs of Weight in 

 Bodies on being melted or heated. In a 'Letter from George 

 Fordyce, ^f.D. F.R.S. to ^/r Jofeph Banks, Bart. P.R.S. 



Read April 28, 17S5. 



SIR, 



ALTHOUGH I have made many experiments on the 

 fubje(£l of the lofs of weight in bodies on being melted, 

 or heated, I do not think it worth while to lay them all before 

 the Society, as there has not appeared any circumftance of 

 contradidion in them. I fhall content myfelf with relating the 

 following one, which appears to me couclufive in determining 

 the lofs of weight in ice when thawed into water, and fubje6t 

 to the leaft fallacy of any I have hitherto made, in fhewing the 

 lofs of weight in ice on being heated. 



The beam I made ufe of was fo adjufted as that, with a 

 weight between four and five ounces in each fcale, _^*-^-^part 

 of a grain made a difference of one divifion on the index. It 

 was placed in a room, the heat of which was ^y degrees of 

 Fahrenheit's thermometer, between one and two in the after- 

 noon, and left till the whole apparatus and the brafs weights 

 acquired the fame temperature. 



A glafs globe, of three inches diameter nearly, with an 

 indentation at the bottom, and a tube at the top, weigh- 

 ing about 45 1 grains, had about 1 700 grains of New- River 

 water poured into it, and was hermetically fealed, fo that the 



B b b 2 whole, 



6 



