Weight In Bodies on being melted or heated. 365 
the furrounding atmofphere, would prefs upon the fcale down- 
ward with the whole force of the difference. If a little more 
than half a pint of air was cooled over the fcale to the heat of 
the ice and glafs containing it, that is, twenty degrees below 
the freezing point, the difference, according to General Roy’s 
table, would have been the eighth part of a grain, ^ which 
was the weight acquired ; but the air within half an inch of 
the glafs veffel being only one degree below the freezing point, 
1 cannot conceive, that even an eighth part of a pint of air 
could be cooled over the fcale to twenty degrees below the 
freezing point ; nor that the whole difference of the weight of 
the air over the fcale could ever amount to the ^ 2 d of a grain. 
I have, however, contrived an apparatus which is executing, m 
Which this caufe of fallacy will be totally removed. I (hall, 
therefore, reft at prefent the ftate of this part of the fubjeft ; 
and leave it only proved, that water gains weight on being- 
frozen. 
1 am, &c. 
G. FORDYCE, 
