Physics and Ohemistry. 143 
SCIENTIFIC INTELLIGENCE. 
I. Puystcs AND CHEMISTRY. 
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. Fs) 
tion of only 16 per cent. in that of chlorine. At high temperatures, 
therefore, the behavior of the halogens would seem inverted, com- 
pared with that at ordinary temperatures. The separation of the 
atom of any other element. Hence chlorine which is the most: 
active of the three halogens is also the least readily dissociated. 
Iodine which forms weak molecules with hydrogen, ethyl, etc., 
. . 
forms a weak molecule with iodine. Bromine is intermediate in 
dissociation of the molecules P, and As, toward P, and As,, Fer- 
rous chloride vapor, which at low temperatures is Fe,Cl,, is FeCl, 
at high ones.—Ber. Berl. Chem. Ges., xiv, 1453, July, 1881. 
G. F. B. 
2. On an Air-thermometer convenient for Chemical purposes.— 
The growing necessity for accurately determining temperatures 
