[ 167 ] 
than a tranfition of bodies from a ftate of fluidity to 
that of firmnefs by the foie interpolation of cold. 
The ice of oily and faline bodies differs greatly 
from that of water, which is friable and eafily broke 
whereas that of mercury is du&ile. And M. Braun 
pioceeds to confider all bodies, which liquify by heat, 
as fo many fpecies of ice; fo that every metal, wax, 
tallow, and glafs, comes within his view, in this re- 
ipect. 
Mercury then is, in its natural if ate, a folid me- 
tal ; but is fufible in a very fmall degree of heat. 
Bvery metal begins to flow in a certain degree of 
heat; but this degree is different in different metals. 
Bure tin begins to run at 420 ; lead, at 530 ; and 
lfmuth, at 470, in Fahrenheit’s thermometer: or 
according to our author, lead liquifies at 320 above 
toe cypher in his fcale, which correfponds with <96 
m Fahrenheit; lead at 170 = 416 of Fahrenheit; 
llmuth at 235 = 4p 4 • zinc requires a greater heat 
to melt it than will make mercury boil. Now, if 
it could be fettled, at what point mercury would be- 
gm.to be congealed, we fhould know the point at 
w ich it began to flow ; as it has been long known, 
that water is either fluid or folid, as the heat of it is 
a very few degrees above or under 32 in Fahrenheit’s 
t ermometer. Juft fo metals become folid, at alrnofl 
the fame degree of heat in which they become fluid. 
But m mercury, the congealing point is at too great 
a latitude to be exactly determined ; but our author 
e imates it to be about 4 69 degrees in his thermo- 
meter; at a lefs degree than which, he has not been 
able to obferve ^ the flighted: congelation. Hence it 
*ollows> that the condenfation or contra&ion, and 
confequently 
