So On (he Freezing of Mercury, &c* 



which gave, on. trial with the thermometer, — 43". The 

 mercury was now received into the cloth, and put gently 

 into this new mixture, where it was left to be cooled mil 

 lower than before. 



In the mean time five pounds of muriat of lime, in a large 

 pail made of tinned-iron and japanned infide and outride, 

 was placed in a cooling mixture in an earthen-ware pan. 

 The mixture in the pan, which confided of 4 lib. of muriat 

 of lime and a like quantity of mow, of the fame temperature 

 as the former, in one hour reduced the 5^b- or " muriat in 

 the pail to — 15°. The mixture was then emptied out of the 

 earthen pan, and four large corks, at proper diftances, placed 

 on its bottom, to fetve as refts for the japanned pail which 

 was now put into the pan. The corks anfwered the purpofe 

 alteady mentioned, that of infulating the inner veffel, while 

 the exterior one kept off the furrounding atmofphcre, and 

 preferved the air between the two at a low temperature. 



To the 5 lib. of muriat of lime which had been cooled as 

 already noticed to — 15 , and which ftill remained in the 

 metallic vefiel, was now added fnow, uncomprefled and free 

 from moifture, at the ufual temperature of + 33°. In lefs 

 than three minutes the mixture gave a temperature of — 6a°: 

 a degree of cold which I believe was never before produced 

 in this country, being 94^ below the freezing point of water. 

 The mercury, which, byimmerfion in thefecond eooling- 

 tuixture to which it was expofed, we found by this time 

 reduced to — 30°, was now, by the means employed before, 

 cautiouflv put into the laft-made mixture of the temperature 

 of — 6i Q . A hoop, with net-work fattened to its upper edge, 

 and of fuch a breadth in the rim that the net- work, when 

 loaded with the bladder of mercury, could not reach its 

 lower edge, was at the bottom of the mixture, to prevent 

 the bladder from coming in contaft with the velfel; by 

 which means the mercury was fufpended in the middle of 

 the mixture. As foon as the bladder was fafely deposited on 

 the net-work, the veffels were carefully covered over with 



4 a cloth, 



