Chemistry and Physics. 209 
ured at the temperature of ebullition. If g is the weight of one 
substance in the distillate, m its molecular weight and p its vapor 
tension at the boiling point ¢ and under the barometric pressure 
6; and if G be the weight of the other constituent, M its molec- 
ular weight and P its vapor tension also at the boiling point, we 
have, by the above law, 
An extended series of experimental results are given, which estab- 
lish the equality of these two ratios. From this equation it fol- 
lows that M= =_— If one of the substances be water, m= 18, 
_ t= 98°2°, the tension of aqueous vapor p = 712-4 mm. and hence 
the naphthalene vapor tension P =6 —p = 733—712°4 = 20°6 mm, 
The molecular weight of water m= 18. Substituting these values, 
_ 18X8°9X712°4 _ ‘ ees oat: 
M = Tsog = 118 The formula C,H, requires 1 
This is an extreme case, but the result shows that the above 
formula, and not any multiple or submultiple of it, is correct. The 
method is capable of indefinite extension.— Ber. Berl. Chem. Ges., 
X, 2098, Jan., 1878. GARE ALE oe 
2. Ona new Oxide of Sulphur, Persulphuric oxide.— BERTHE- 
Lor has described a new oxide of sulphur which he calls persul- 
. 
phuric oxide, corresponding to perchromic and permanganic 
: ric 
of absolutely dry sulphurous oxide and oxygen uty oA § 
e electrolysis of con- 
centrated sulphuric acid, and has been confounded with the so- 
s also fe 
les, many centimeters long and of an apprec - 
often crossing the tube. It resembles sulphuric oxide, but th - 
ter is opaque, in finer needles, shorter and narrower. It 
4 considerable vapor tension and sublimes spon 
* Ann. Chim. Phys., V, xii, 463, December, 1877. 
Au, Jour. Sct.—TaIrD sees ts Vou. XV, No. 87.—Mancu, 1878. 
