French National Institute. 273 
eolide, the snail, the Linnea, and the planorbus. The two 
former were very little known even externally ; and the 
author has rectified the false ideas of naturalists concern- 
ing them. 
In the second branch he has treated of the fossil bones of 
the bear; the rhinoceros, and the elephant. 
Two sorts of bears hitherto unknown have been buried 
along with tigers, hyenas, and other carnivorous animals itt 
a great number of caverns in the mountains of Hungary and _ 
Germany. 
Bones of the rhinoceros and elephant are found in abun- 
dance in every part of the globe. The author has collected 
the names of several hundred places of both continents 
where the fossil bones have been found. (See Philosophical 
Magazine, page 158 of the present volume.) 
M. Fourcroy has given a new edition of his Chemical 
Philosophy ; the shortest, most methodical, and most fre- 
quently used elementary book in the science. The two 
principal agents in chemistry,—affinity, which unites the 
molecula of bodies, and fire, which separates them,—have 
been this year the subject of new and important researches. 
We know that ice is lighter than water, since it floats 
upon it: on the other band. warm water Is generally lighter 
than cold: But does this liquid always condense in propor- 
tion as it cools, in order suddenly to dilate itself at the in- 
stant of its freezing? 
We may doubt this ; and in fact it is not the case; itis 
some degrees above the freezing point that water is at its 
maximum of density. M, le Febvre-Gineau has directly 
proved it these some years past by means of the thermome- 
ter and the hydrostatic balance; and count Rumford has 
suggested an experiment which makes the fact very evident. 
A thermometer has its bulb placed directly under a tube 
suspended by a strip of linen, and the whole is placed in 
water ready to freeze. The surface of this water, opposite 
to the opening of thé tube, is touched with a body heated 
only to three or four degrees ; the molecules of water heated 
by this contact descend into the tube and act upon the ther- 
Vol. 26. No. 103, Dec, 1806, § mometer, 
