the Icji Methods of pr:iiuchig A<i'ificlal CoU. 505 



• June 29, 1792, temperature of the air 71 degrees, I funk a thermometer (the bulb being 

 covered with fine lint tied over it and clipped clofe round) by dipping it in ether,, and fan- 

 ning it to 26 degrees ; then by expofing the thermometer to the brilk thorough air of an open 

 windowr, to 20 degrees ; and again, by ufing fome of the fame ether, but which had been 

 purified by agitating it with eight times its weight of water, applied exa£lly as in the lad 

 experiment, the thermometer funk to 12 degrees. Water tried in the fame manner at the 

 fame temperature, funk the thermometer to 56 degrees. 



A whirling motion was given the thermometer during each experiment. - 

 The lint was renewed for each experiment, and the bulb required to be dipped into the 

 ether thrice ; the firft time fufliciently to foakit ; after which the thermometer was held at 

 the window till it ceafed to fink ; then a fecond quick immerfion, and likewife a third, ex- 

 pofing the thermometer in like manner after each immerfion. 



In this manner, a little water in a fmall tube may.be frozen prefently, by good ether not 

 purified, at anytime, cfpecially if a fmall wire be ufed to fcratch or fcrapc the fides of the 

 tube below the furface of the water. 



During the warmcft weather of laft furamer, I frequently froze water in this way. 



Explanation of Plate XX. 



FIG. I. is aveflel in one piece, open at the bottom ; n a the body, holding, when inverted, 

 two pints ; b the tube, holding five ounces ; the lower or fmaller part (formed by a contraaibn 

 or leflening of the tube in diameter, merely for the purpofc of leaving a fmall flioulder for 

 a temporary partition), holding rather lefs than one-fifth of the whole. 



Fig. 2. is a vefTel confiding of two parts ; a « the body, holding two pints ; h the tube, 

 holding five ounces ; which, together with the lid c, forms a cover to take oiT and on the 

 veflel. 



N. B. This veflel may, if preferred, be ufed inftead of fig. i. the parts correfponding with 

 it, except in not being open at bottom, and the continuation of the tube upwards juft fuffi- 

 cient to ferve for a handle. 



Fig- 3- is a veflel in one piece, open at the bottom, holding, when inverted, two pints ; 

 b the tube, holding four ounces and a half. 



Fig. 4. a veflel open at bottom, holding, inverted, one pint. 



Fig. 5. a cover to fig. 4. a a the body, fitting exactly over, and b the cup-part (holding 

 three ounces) fitting exaiQly within the correfponding parts of fig. 4. 



Fig. 6. the inftrument for grinding the ice into powder ; it works upon a fliort centre- 

 point, and has the edge bevilled contrary ways on each fide the point, fo ?s to follow. Th« 

 finenefs of the powder is regulated by "the degree of prcftlire ufed. Tiie handle is wood, 

 tiic reft metal ; n is a Aiding cover fitting on the tube in which the ice is ground, to exclude 

 the external air, and to keep the inflrumcnt fteady ; b is the flioulder or guard, to prevent 

 the point cf the inflrument froin touching fo as to endanger injuring ^the bottom of the 

 tube. It (hould be madefo as to fit without grating the infidt of the tube in ufing. 



The tubes of each of the vcfl'els (lituld be fomcwhat flinricr tlian tlic vtflcl, fo a? not 

 quite to reach the bottom of it. 



Fig. 7. a thermomcter-giafs, with the bulb three-fourths full of quickfiiver. 



Fig. 8. a thermometer with the lower part of the ftale-board turned up with \ Jiiiipe, 



Vol.. I. — Fi-BRUARy t79K. I'V i;,r 



