Chemistry and Physics. 805 
grams, 317°5, and benzene seventy-eight grams, 776 calories. In 
the formation of the hydrogen compoun nds of bromine and iodine 
H+Br gas=HBr gas yields 13:1 calories, while H+Br liquid 
=HBr gas gives 9°5, H+I gas =H gas gives Aggy 9 calories, and 
H-+I solid =HI gas ives —6°3. The heat of formation of 
bromic acid is —21-2, and * hypobromous PI ga gh tig 
Chim. Phys., V, xiii, ‘ Jan. 
2. Relations between the pipe Weights of the Ble neat 
WarcuTER has described certain additional relations between the 
(i. e., one positive and the other Pein) are a equal to one 
fusing and the boiling points of the elements, so far as known, 
increase With increasing atomic weights and increas ig V3 ge 
fr 
atomic weights, the greater, the higher the valence. 6th. 
crass of the negative metallo ids—fluorine to silicon—for the 
e roper, diminishes be * Rae atomic weight and an 
increasing valence.—Ber. B Fes., Xi, 11, Jan. Ne 
B. 
8. New Method for the Preparation of Nitrogen. s eesaes SE 
has observed that when ammonium nitrate and manganese perpide 
are heated together up to the fusing point ais the former (about 
180°) a violent reaction age the mass mes red hot and 
nitrogen is evolv the temperature be oe t between 180° 
ee 200°, yea nitrogen is entirely pure, being formed according to 
€ equatio 
On H NO,),+Mn0, =Mn(NO,),+(H,9).+N. 
One experiment, three grams NO, heated with an equal 
weight of MnO, in a acti & bath kept at 205°, yielded 630 
cubic centimeters of gas, nearly a theoretical quantity. If the 
nous nit 
temperature rises above 216° 8 decomp — 
giving sachin vapors and ox sg At td the gas contai 
sp og per t of oxygen.— Bull. Soe. Ae, Eh xxi, a — 
187 P. 
i “On a Method 0 separating Crystallized Silica, patois 
Quart, from Siltoaten- —Lavurer has suggested an improvement 
os 
