556 
MERCURY. 
pushed upwards with a sort of violence. He also 
placed upon the gallery, and on the north side of 
his house, some quicksilver in an open bowl. 
Within an hour he found the edges and surface of 
it frozen solid ; and some minutes afterwards the 
whole was condensed by the natural cold into a soft 
mass very much like tin. While the inner part 
was still fluid, the frozen surface exhibited a great 
variety of branched wrinkles ; but in general it re- 
mained pretty smooth in freezing. The congealed 
mercury was more flexible than lead ; but on being 
bent short it was found more brittle than tin ; and 
when hammered out thin it seemed somewhat gra- 
nulated. When the hammer was not perfectly 
cooled, the quicksilver melted away under it in 
drops ; and the same thing happened when the 
metal was touched with the finger, by which also 
the finger was immediately benumbed. When the 
frozen mass was broken to pieces in the cold, the 
fragments adhered to each other, and to the bowl in 
which they lay. In the warm room it thawed on 
its surface gradually, by drops, like wax on the fire, 
and did not melt all at once. Although the frost 
seemed to abate a little towards night, vet the con- 
gealed quicksilver remained unaltered, and the ex- 
periment with the thermometer could still be re- 
peated. On the seventh of December the professor 
continued his observations ; but some hours after 
sunset a north-west wind sprung up, which raised 
the thermometer to — 46°, when the mass of quicksil- 
ver began to melt. 
