VOL. LI.J PHILOSOPHICAL TRANSACTIONS. 48 1 



went further in order to examine the quicksilver when it was made solid. He 

 poured quicksilver into a glass tube as thick as one's finger, closed at bottom, 

 but open at top. The quicksilver in this cylinder, which was about one nich 

 and half long, froze in three quarters of a minute ; and he observed that it be- 

 came solid, perfectly resembling other metals, except iron : it continually con- 

 tracted, and its surface, which was at first pretty high, soon sunk very low. 

 This cylinder of frozen quicksilver sunk to the bottom of fluid quicksilver, in 

 the same manner as is observed of other metals except iron. We know the con- 

 trary happens with regard to water frozen and other fluids, which extend as 

 they become solid, and their ice swims in the fluid matter of which they were 

 produced. 



Dec. 26 in the morning, between 9 and 10, the cold became extremely sharp 

 at211^ and such as exceeded the greatest degree of artificial cold fixed by 

 Fahrenheit ; for 40° below zero, in Fahrenheit's thermometer, is equal to 210** 

 of that of De Lisle. 



Mr. Braun repeated this experiment again exactly with the same success with 

 that of the day before. The counsellor and professor Lomonossow made the 

 same experiment on the same day ; and by means of aquafortis the cold came to 

 495 degrees. He then poured in spirit of common or sea salt, and the quick- 

 silver fell down in the thermometer to 554 degrees ; and in taking the thermo- 

 meter from the mixture the quicksilver continued to fall in the open air to the 

 5 5 2d degree. He threw yet into the glass a little more snow, pouring on it 

 some oil of vitriol, and suddenly the quicksilver fell to 1 260 degrees. He then 

 broke the ball, and found the mercury changed to a solid body. The quicksilver, 

 which yet remained in the tube, was also become solid, and appeared like a loose 

 silver wire attached to the ball, which was flexible every way. He gave the ball 

 of quicksilver several blows with a turned ax, and it became flat like a half ruble 

 or English half crov/n ; but receiving thereby some cracks, it dissolved in about 

 20 minutes. These experiments were made when the air was at about 208 de- 

 grees of cold. 



It must be remarked that distilled quicksilver only was made use of in every 

 experiment; nay in some the quicksilver was revivified from sublimation. There 

 can therefore be no suspicion that what they used was impure or mixed with any 

 heterogeneous matter. This appears to have happened to Mr. De Lisle de la 

 Croyere, when he says, that in Siberia he found the quicksilver congealed in the 

 barometer: and even his papers, which are in the academy, show that he made 

 a mistake in his remarks; for according to them the mercury became solid as 

 soon as it fell to about 195''or200": but the mercury which is pure does not 

 congeal at that degree ; for otherwise it would not be very extraordinary with us 

 to see it take a solid form, beca^^se it is not rare to find the cold at this degree 



VOL XI. 3 Q 



