The Chemistry of Powder and Explosives - Sciencemadness Dot Org

NITROGLYCERIN 197
are evolved, but that, if syrupy glycerin is added to a mixture of
two volumes of sulfuric acid (d. 1.84) and one volume of nitric
acid (d. 1.50) with stirring while the mixture is kept below 0°,
then the results are entirely different, the glycerin dissolves, and
the solution when poured into water gives an oily precipitate of
nitroglyccrin. He collected the oil, washed it with water until free
from acid, dried in a vacuum over sulfuric acid, and procured a
transparent liquid of the color and appearance of olive oil. (Pure
nitroglycerin is water-white.) Sobrcro reported a value for the
density which is very close to that which is now generally accepted,
observed the ready solubility of nitroglyccrin in alcohol
and its rcprecipitation by water, and reported a number of its
chemical reactions—its comportments with acid and with alkali,
that
It detonates when brought into contact with metallic
potassium, and evolves oxides of nitrogen in contact with
phosphorus at 20° to 30°C, but at higher temperatures it
ignites with an explosion. . . . When heated, nitroglyccrin
decomposes. A drop heated on platinum foil ignites and
burns very fiercely. It has, however, the property of dctunating
under certain circumstances with great violence. On
one occasion a small quantity of an ethereal solution of
nitroglycerin was allowed to evaporate in a glass dish. The
residue of nitroglycerin w'as certainly not more than 2 or 3
centigrams. On heating the dish over a spirit lamp a most
violent explosion resulted, and the dish was broken to atoms.
. . . The safest plan for demonstrating the explosive power
of nitroglycerin is to place a drop upon a watch glass and
detonate it by touching it with a piece of platinum wire
heated to low redness. Nitmglyeerin has a sharp, sweet,
aromatic taste. It is advisable to take great care in testing
this property. A trace of nitroglycerin placed upon the
tongue, but not swallowed, gives rise to a must violent pulsating
headache accompanied by great weakness of the
limbs.
For many years Sobrcro kept in his laboratory and guarded
jealously a sample of the original nitmglyeerin which he had
prepared in 1847. In 1886 he washed this material with a dilute
solution of sodium bicarbonate and took it to the Nobcl-Avigliana
factory, of which he was a consultant, where he gave verbal
testimony of its authenticity and where it has since been stored