828 Report of the Committee 
the latter had boiled long: neither did any difference feerct 
to arife from the water containing fuch fubflances as are, 
difpofed to part readily with their phlogifton; for, on 
trying the thermometers in the fleam of diflilled water, 
their height was not fenfibly altered by pouring in a 
fm'all quantity of a folution of liver of fulphur, or of 
iron filings imperfedtly rafted. The thermometer, how- 
ever, feemed to Hand fenfibly lower in pump water be- 
ginning to boil, than in the fame water long boiled, but 
the difference fcarcely exceeded -^th or jth of a degree. 
We made fome experiments to determine the heat of 
water boiling in open veflels. In general, when the 
veffel was almoft full, and the water boiled fail, and the 
ball of the thermometer was held from three-quarters to 
two or three inches, under water, and alfo in that part 
of the veffel where the current of water afeended up- 
wards, that is, in the hottefl part of the water, its heat 
was not much different from that of the fleam of water 
boiling in clofed veffels, varying only from a quarter of a 
degree more than that, to as much lefs ; but if the water 
boiled gently, its heat would frequently be half or three- 
quarters of a degree cooler than the fleam. If the ex- 
periment was tried in the deep pot with fuch a quantity 
of water in it that the furface was at leafl 14 or 1 5 inches 
below the top, of the pot, fo that though the veffel was 
open* 
