VOL. LXXIV.] PHILOSOPHICAL TRANSACTIONS. 581 



well glazed, and is represented in fig. I, pi. 8. a, is a large funnel, filled witli 

 a solid mass of ice. b, a cavity in the middle of this ice, formed, part of the 

 way, by scraping wifch a knife, and for the remaining part, by boring with a hot 

 iron wire, c, one of my thermometer pieces, which serves for the heated body, 

 and rests on a coil of brass wire: it had previously been burnt with strong fire, 

 that there might be no danger of its suffering any further diminution of its bulk 

 by being heated again for these experiments, d, a cork stopper in the orifice of 

 the funnel, e, the exterior vessel, having the space between its sides and the 

 included funnel a, filled with pounded ice, as a defence to the ice in the funnel. 



f, a cover for this exterior vessel, filled with pounded ice for the same purpose. 



g, a cover for the funnel, filled also with pounded ice, with perforations in the 

 bottom for allowing the water from this ice to pass down into the funnel. 



The thermometer piece was heated in boiling water, taken up with a pair of 

 small tongs equally heated, dropped instantly into the cavity b, and the covers 

 put on as expeditiously as possible; the bottom of the funnel being previously 

 corked, that the water might be detained till it should part with all its heat, and 

 to prevent the water from the other ice, which ran down on the outside of the 

 funnel, from mingling with it. After standing about 10 minutes, the funnel was 

 taken out, wiped dry, and uncorked over a weighed cup: the water that ran 

 out weighed 22 grains. Thinking this quantity too small, as the piece weighed 

 72 grains, I repeated the experiment, and kept the piece longer in the funnel; 

 but the water this time weighed only 12 grains. Being much dissatisfied with 

 this result, I made a 3d trial, continuing the piece much longer in the cavity; 

 but the quantity of water was now still less, not amounting to quite 3 drops; and 

 to my great surprize I found the piece frozen to the ice, so as not to be easily 

 got off, though all the ice employed was, at the beginning of the experiment, 

 in a thawing state. 



I had prepared the apparatus for taking the boiling heat of mercury; but being 

 entirely discouraged by these very unequal results, I gave that up, for the pre- 

 sent at least, and heating the piece to 6° of my thermometer, turned it quickly 

 out of the case in which it was heated into the cavity, throwing some fragments 

 of ice over it. In about half an hour, I drew off the water, which amounted to 

 11 pennyweights; then stopping the funnel again, and replacing the covers, I 

 left the whole about 7 hours. At the end of that time, I found a considerable 

 quantity of water in the funnel : the melting of the ice had produced a cavity 

 between it and the sides, great part of the way down, which, as well as that in 

 the middle, was nearly full. Yet the water ran out so slowly, that I apprehended 

 something had stopped the narrow end of the funnel, but the true cause became 

 afterwards apparent on examining the state of the ice. The fragments which I 

 had thrown over the thermometer piece were frozen entirely together, and in 



