Chemistry and Physics. 593 
7. Refraction of compressed water.—Mascart has combined the 
o a change much greater than that resulting from the experi- 
ments of M. Grassi. The same effect was obtained whether the 
pressure was transmitted by a column of water or a mass of air. 
Assuming the laws of the refractive powers, or that n? —1 is pro- 
portional to the density, the compressibility “~=-0000518. As- 
suming that n—1 is proportional to the density gives v’=-0000453. 
The first result is very nearly that obtained by Jamin, but Grassi, 
direct experiment, found ~=*0000471, so that neither hypo- 
thesis seems to be exact. 
to the gradual return of the liquid to the temperature of t r- 
rounding medi At 16° a fall of pressure of 4°3 rs pr 
duced in t y a motion of 1:9 bands; hence the index of 
is wa 
refraction had diminished *00000056. From the experiments of 
Gladstone and Dale it follows that this corresponds to a change in 
temperature of -00110°. A computation gives a result ‘00109. 
The closeness of this agreement is however accidental, as the posi- 
tion of the bands could only be determined to one-tenth.— Comptes 
B.C. BP, 
8. Maximum of density of water.—Prof. Macu has determined 
Mondes, 506. Si Gi Be 
9. Gaseous, Liquid and Solid States of Water-substance.— 
Prof. J. Tuomson recently communicated to the Royal Society a 
