Physics and Chemistry. 145 
not = peepee the inflammable. But upon the addition of a f 
drops of nitric acid to the mixture the gas emer: psa rae 
— Ber. Berl. Chem. Ges., xiv, 1757, Sept., 1 81. i 
On Ammonium tribromide. a teste finds cha oer: to 
a saturated solution of ammonium bromide, sufficient bromine is 
added to form H,NBr,, and the whole is plac ced over sulphuric 
acid “hy a bs : days, lar ge prismatic crystals are formed, havin 
the color of ee dichromate. The heat of thei formation 
is considera Vhen a solution ot 9.8 grams ammonium 
bromide in 13° 93 grams water is mixed with 8°39 grams bromine, 
the temperature rises from 20° to 28°6° C. At o ordinary tempera- 
tures the pat hiar lose the excess of bromine in from one to two 
hours; at 50°, in ten minutes. They are not hygroscopic and 
ve readily i in water. By drying the stad in an atmo- 
Thi 
tribromide was put into a solution of potassium iodide. 
results confirmed the formula H,NBr,. No dibromide appeared 
to be formed, but from the continued solution of the bromine 
With additional evolution of heat, the author infers the existence 
of a cera blenny, HN Br, —Ber. Berl. Chem. Ges., xiv, 2398, 
Nov., G. F. B. 
6. ‘On ve dertarke b of the Caucasus.—BrILsTEIN and Kur- 
BATOw have continued their examination of the petroleum found in 
the Caucasus and pve ve now given the results of their investiga- 
examined were obtained. "This etroleum is much lighter than 
that from Baku and yields a larger quantity of volatile fractions. 
Three of these were at first obtained, boiling respectively between 
_ 30°-35°, 70°-75° and 95°-100°. The first fraction consisted of pen- 
tane, and was a mixture of nearly equal parts of normal pentane 
and isopentane. From the second fraction hexane was isolated ; 
Series corresponding to the formula Yn ns the Tiquid was treated 
with bromine and with concentrated nitrie acid in order to de- 
Stroy them. The suspicion was confirmed by the fact that after 
this ‘treatment the liquid possessed all the properties vid normal 
hexane. The third fraction consisted of heptane, from which, by 
treatment with fuming sulphuric acid, traces of bet ne stare tolu- 
ene were obtained. It would reel h appear shat en etroleum 
essentially of the ape nal C nli.,+,, like American petroleum, 
ut contains small quantities of the aromatic hydrocarbons C,H,,_, 
and their addition- products ©, H,,. Treatment of the crude e petro- 
leum with nitricacid of 1°52 sp. gr. gave volatile crystals, which were 
Obtained in relatively greater quantity from the fraction boiling 
