MERCURY. 
555 
brought into a warm room. Whenever the door 
was opened a fog suddenly formed round it. Du- 
ring the day, short as it was, parhelia and haloes 
round the sun were frequently seen ; and in the 
night mock-moons and haloes about the moon. 
Finally, our thermometer, not subject to the same 
deception as the senses, left us no doubt of the ex- 
cessive cold ; for the quicksilver in it was reduced 
on the fifth of January (old style) to — 120° of Fah- 
renheit’s scale, lower than it had ever been observed 
in nature.” 
The phenomenon of the natural congelation of 
quicksilver has since been more particularly noticed 
by professor Pallas, who, in the year 177 2 > was sent 
by the empress of Russia, with some other gentle- 
men, on an expedition similar to that of M.Gmelin. 
M. Pallas remarks, that at Krasnoyarsk, on the 6‘th 
and 7 th of December of the above-mentioned year, 
there happened the greatest degree of cold he ever 
experienced in Siberia : the air was calm at the 
time, and seemingly thickened, so that, though the 
sky was in other respects clear, the sun appeared as 
through a fog. He had only one small thermometer 
left, in which the scale went no lower than — 7°; and 
on the sixth, in the morning, he observed that the 
quicksilver had sunk into the ball, except some 
short columns which stuck fast in the tube. When 
the ball of the thermometer, as it hung in the open 
air, was touched with the finger, the quicksilver 
rose; and it could be seen that the solid columns 
stuck and resisted a good while, and were at length 
