CHAPTER VII.

ANALYSIS OF EXPLOSIVES.

Kieselguhr Dynamite—­Gelatine Compounds—­Tonite—­Cordite—­Vaseline—­ Acetone—­Scheme for Analysis of Explosives—­Nitro-Cotton—­Solubility Test—­ Non-Nitrated Cotton—­Alkalinity—­Ash and Inorganic Matter—­Determination of Nitrogen—­Lunge, Champion and Pellet’s, Schultze-Tieman, and Kjeldahl’s Methods—­Celluloid—­Picric Acid and Picrates—­Resinous and Tarry Matters—­ Sulphuric Acid and Hydrochloric Acid and Oxalic Acid—­Nitric Acid—­ Inorganic Impurities—­General Impurities and Adulterations—­Potassium Picrate, &c.—­Picrates of the Alkaloids—­Analysis of Glycerine—­Residue—­ Silver Test—­Nitration—­Total Acid Equivalent—­Neutrality—­Free Fatty Acids—­Combined Fatty Acids—­Impurities—­Oleic Acid—­Sodium Chloride—­ Determination of Glycerine—­Waste Acids—­Sodium Nitrate—­Mercury Fulminate—­Cap Composition—­Table for Correction of Volumes of Gases, for Temperature and Pressure

Kieselguhr Dynamite.—­The material generally consists of 75 per cent. of nitro-glycerine and 25 per cent. of the infusorial earth kieselguhr.  The analysis is very simple, and may be conducted as follows:—­Weigh out about 10 grms. of the substance, and place over calcium chloride in a desiccator for some six to eight days, and then re-weigh.  The loss of weight gives the moisture.  This will generally be very small, probably never more than 1 per cent., and usually less.

Mr James O. Handy, in order to save time, proposes to dry dynamite in the following manner.  He places 1 grm. of the material in a porcelain crucible 1 inch in diameter.  The crucible is then supported at the bottom of an extra wide-mouthed bottle of about 600 c.c. capacity.  Air, which has been dried by bubbling through strong sulphuric acid, is now drawn over the surface of the sample for three hours by means of an ordinary aspirator.  The air should pass approximately at the rate of 10 c.c. per second.  The tube by which the dry air enters the bottle extends to within 1 inch of the crucible containing the dynamite.  An empty safety bottle is connected with the inlet, and another with the outlet of the wide-mouthed bottle.  The first guards against the mechanical carrying over by the air current of sulphuric acid from the acid bottle into the sample, whilst the second prevents spasmodic outbursts of water from the exhaust from reaching the sample.  The method also gave satisfactory results with nitro-glycerine.  The dry substance may now be wrapped in filter paper, the whole weighed, and the nitro-glycerine extracted in the Soxhlet apparatus with ether.  The ether should be distilled over at least twenty-four times.