8o ELEMENTARY ORGANIC ANALYSIS

COMBUSTION OF EXPLOSIVE BODIES

Compounds, such as diazo and nitro bodies, that
explode on heating must be mixed or diluted with
some inert material such as powdered lead chromate,
cupric oxide, or quartz.
Fine cupric oxide' is mixed with the material which
is best placed in a long copper boat. At times the
mixture is separated by dams of pure cupric oxide to
isolate small portions.'

Picric acid and picramid and allied bodies are easily
burned when mixed with three or four volumes of
finely powdered quartz.3

For the combustion of the more explosive compounds such
as nitroglycerine, etc., recourse must be had to one of the
special methods ; for instance, that of Hempel,* of burning
in a vacuum.
CALCULATION OF RESULTS

As three-elevenths of the carbon dioxide is carbon
the per cent, of this element is found by means of the

formula :

„ ^ - wt. carbon dioxide X 300

Per cent, carbon = r-— — — ^^—.
wt. substance X n

As one-ninth of the water is hydrogen the per cent

of this element is found by means of the formula :

wt. water X 100



Per cent, hydrogen



wt. substance X 9



1 Schwarz : Ber. d. chem. Ges., 13, 559 ; Janowsky : Monatshefte, 6, 462 ;
Ibid., 9, 836 ; Kder : Ber. d. chem. Ges., 13, 172.
8 Jackson and I«amar (Am. Chem. J., 18, 676), in burning dinitrophloroglu-
cindiethylester, found this procedure necessary.
« Am. Chem. J., a3, 346.
* Ztschr. anal. Chem., 17, 414.
