266 Scientific Intelligence. “ 
pressibility of water from the optical experiments, we find the coefficient 
to be 0°0000500 for common distilled water and 0°0000511 for water 
deprived of air. According to the direct measures of Grassi this coefli- 
of 8 
fringes between dry and saturated air. More than fifty measurements 
made under very different circumstances of temperature, pressure, and 
of 
d 
vapor would only affect the seventh decimal of the nunber 1°000292 ... 
found for that index, and that consequently in astronomical refractions It 
f useless to trouble oneself about the vapor of water.— Comptes Rendus, 
xlv, 892, 
On the density of the vapors of certain bodies—DeviLte and Troost 
* ; ra) th densi- 
containing the substance into the vapor of some other substance W 
boils at a high temperature without decomposition. In this manner no 
thermometer is necessary. The authors employ for this purpose su'P be 
t 440° U,, 
ord 
latter at 350°, ‘The apparatus used consists of a mereury ra the ial 
o hold the 
he bottle. 
upper part of the bottle to earry off the vapor of the mereury % 
phur for condensation; one kilogram of sulphur and one or two 
