Chemistry and Physies. 233 
SCIENTIFIC. INTELLIGENCE. 
I. CHEMISTRY AND PHysics. 
On a Relation between the Molecular weight of L iquids and 
their Velocity of Evaporation. —On distilling successively in the 
me apparatus given volumes of benzene and of water, Scuann 
found that, even when the boiling was maintained as nearly 
uniform as possible, very different weights of these two substances 
passed over in the same time. Even in a rough experiment, the 
quantity of benzene in the receiver was double | that of the water. 
With a view to give the experiment greater exactness, the time 
exact time of evaporation of equal weights parison, the 
values’ thus obtained appeared to be very nearly in the inverse 
Tatio of the molecular weights of the Ls a emplo; ed hus 
orated in 12°7, 12:95 and 12°3 minutes ; ane the same ages 
chloroform, boiling pola 61°5° and density 1°4048, craporsted b in 
143, 14-5 and 14°3 minutes. Or, pedo, to eqns) weights, i in 8°25, 
84 and 828 m minutes. Since m:m' t, the first value gives 
for the molecular weight of bblnedtornt iio 84, the second 120°25, 
and the third 115: 88; the true value bein 119°5. Benzene, when 
compared with carbon disulphide, boiling point 45°3° and am 
12212, evaporated in 12°3 minutes, whi le the same volume of C 
Tequi red 19 minutes ; or 12°66 reduced to equal weights. This 
0 
26 minutes reduced to equal weights. This gives a molecular 
Weight of 17- 3 he vol 
f 68 instead of 18. Moreover, the ratio of the volumes 
hs Saale muvee evaporated in fies: times is the ratio of their molecu- 
F volum Thus the ratio for benzene and chloroform above 
Sven, is obs : hues et 126:1::95°94 (the molecular vol- 
Seki of benzene) 285-2 the molecular volume of chloroform) ; 
hitf obtained 84°65. The author has further observed that on 
Mately ‘constant, hax | water gives 536°67 7X 18-= 9660" ere 
_ aleohol gives 214-3 46=9857°8. Acetone gives 7523°76, silane oe 
ie Nae 5 and carbon tetrachloride 7161. Ethyl oxide oe sss co: 
Sseipbide 6361-2 and ethyl chloride 6128-79. 
chloride 11736 hyl ‘ an 
6'4, arsenous auianids 12292°99 and ethyl acetate 
a9 fe Phosphorous ceed 8970°5 and ethyl iodide 8938°8. 
1884. 
Jour. 7 —Turep Serres, V AAO No. 159.—Marcu, 
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