142 On the Caiitr action which takes place in MercunJ 



contracted than mercury by abstraction of treat, and attri- 

 bute to that the difference of loss of weight, then, in com- 

 paring 30i24 of mercury with water, there is a variation in 

 the contraction of these two fluids expressed by 4*7 loss of 

 weight in passing through 150 degrees of temperature. In 

 comparing 1000 of mercury with water, a variation of loss 

 in 150* is expressed by l'554i?. 



G. The following experiment was made before many of 

 my philosophical friends with mercurv, described before, of 

 the specific gravity of 13*613, suspended by a very fine wire 

 10 inches long, weighing only ^V of a grain ; — the baro- 

 meter standing at 29*8, the thermometer at 35. 



1000 grains of mercury with 750 grains of alcohol, as be- 

 fore described, were put into a thiri glass vest^el, made for 

 the purpose, round at the bottom, and increasing in diameter 

 gradually to near the top, so that the mercury might l«e 

 easily suspended in the alcohol by a wire introduced into it 

 whilst fluid. These were placed in the centre of a mix- 

 ture of 4 pounds of snow and 4 pounds of muriate of lime, 

 at If o'clock at noon : at 5 minutes past a thermometer 

 placed in the frigorific mixture fell to 5^° below zero, then to 

 54 and to 60. The mercury in the tube of the thermome- 

 ter appeared frozen : it was withdrawn, and when exposed 

 to the air a few seconds, suddenly fell to 140*^ on the scale, 

 in consequence of the mercury in the tube again becoming 

 fluid, and occupying the vacuum which had been occasioned 

 by the contraction of the mercury in the bulb after that which 

 was in the tube had become solid : it was then immediately 

 returned to its place in the mixture of snow and nmriate of 

 lime ; it had remained at 1 40° for several minutes when taken out 

 and exposed to the air, so that the mercury still in the tube was 

 airain made fluid j it instantaneously sunk into the bulb 

 much below 270^, the lowest point on the scale. During 

 this time the mercury and alcohol, very much reduced in 

 temperature, were removed from the above mixture^ and 

 placed in a second mixture of 3 pounds of snow and 3 

 pounds of muriate of lime : the whole was then placed in 

 the first mixture; and at the moment of the crystallization 

 of the mercury, the wire, already partly attached, was by 



raising 



