Chemistry and Physics. 149 
mixture of oxygen and hydro n, as —— that ri ie of 
when th t 0° an m. 
ean of five experimen nts, the heat of combustion found 
Was 2°02930 gram-calories, with a probable error of 0°0018. That 
is, one cubic centimeter of pert SN a at 0° and 780 mm. on 
duces 33°982 units of heat (gram-calories); a close agreement 
with the number —s by Andrews, 33°970.— Ber. Berl. Chem. 
Ges., x, 947, Ma , 
apor theres and Avogadro’s Law. —The law of 
cous state, contain the same number of molecul rom which it 
follows that the molecules of all a in the gaseous state are of 
the same size ence calling the me of hydrogen mole- 
ments, yielding two or more bodies, the molecule of each of 
which has a volume of two. Troosr has submitted this point, in 
the of chloral hydrate, to ves test of experiment, in a very in- 
way, by introducing into the vapor of this body, a salt 
dis 
containing ater, whose disso catertouion , as p 
ble, equal to that of the aqueous vapor of the — mi rate, 
€ vapor of the chloral age suffers dissociatio 0) 
" as such, its vapor is free from water and on introducing the salt it 
wil up water and the volume will increase till the dissocia- 
tion-tension is reached, The salt chosen was potassium oxalate, 
20,0,+H,0, whose aeereaeesene at 78° is 53 mm. and 
at 100° 182mm. The experiments were conducted in Hofmann’s 
Vapor densit apparates, in i woth alcohol vapor and ee nd 
h ¢ ‘Sie was the same; the volume increased 0 
"he ! 
te is a without decomposition.—Ber. J aged 
€8., x, 899, May, 877. 
3. ‘On Plato- Fido titipoayt tn and Triplat to-octonitrooylic ‘nesal 
~—By the action of an alcoholic solution of iodine upon potassium 
