int as 185 deg.. He used the apparatus devised by Horsley. The
heat of formation of nitro-glycerine, as deduced from the heat of
combustion by M. Longuinine, is 432 calories for 1 grm.; and the heat of
combustion equals 1,576 cals. for 1 grm. In the case of nitro-glycerine
the heat of total combustion and the heat of complete decomposition are
interchangeable terms, since it contains an excess of oxygen. According to
Dr W.H. Perkin, F.R.S.,[B] the magnetic rotation of nitro-gylcerine is
5,407, and that of tri-methylene nitrate, 4.769 (diff. = .638). Dr Perkin
says: "Had nitro-glycerine contained its nitrogen in any other combination
with oxygen than as -O-NO_{2}, as it might if its constitution had been
represented as C_{3}H_{2}(NO_{2})_{3}(OH)_{3}, the rotation when compared
with propyl nitrate (4.085) would be abnormal."

[Footnote A: _Jour. Soc. Chem. Ind._, June 1896, p. 471.]

[Footnote B: _Jour. Chem. Soc._, W.H. Perkin, 1889, p. 726.]

The solubility of nitro-glycerine in various solvents has been
investigated by A.H. Elliot; his results may be summarised as follows:--

_______________________________________________________________________
| |
Solvent. | Cold. | Warm.
_____________________________|______________________|__________________
| |
Water | Insoluble | Slightly soluble
Alcohol, absolute | Soluble | Soluble
" 93% | " | "
" 80% | Slowly soluble | "
" 50% | Insoluble | Slightly soluble
Methyl alcohol | Soluble | Soluble
Amyl " | " | "
Ether, ethylic | " | "
" acetic | " | "
Chloroform | " | "
Acetone | " | "
Sulphuric acid (1.845) | " | "
Nitric acid (1.400) | Slowly soluble | "
Hydrochloric acid (1.200) | Insoluble, decomposed| Slowly soluble
Acetic acid, glacial | Soluble | Soluble
Carbolic acid | " | "
Astral oil