2141. To Prepare Gun-Cotton

2141.    To Prepare Gun-Cotton. The simplest way consists in immersing, for a few seconds, well-carded cotton in a mixture of equal parts, by volume, of oil of vitriol of specific gravity 1.845, and nitric acid of specific gravity of 1.500. The cotton, when well saturated, is to be removed and squeezed to repel the excess of acid, and then well washed in clean cold water, until the water no longer reddens litmus paper. It is then dried at a heat not exceeding 212°. A lower temperature is still safer. The cotton thus prepared explodes well, but does not dissolve easily in ether. Under Collodion will be found other preparations of Gun-Cotton.

2142. Nitro-glycerine

2142.    Nitro-glycerine. This is an oily, colorless liquid, with a specific gravity of 1.60. It has no smell, but a taste which at first is sweet, but soon becomes pungent, like pepper; is soluble in ether and methylic alcohol, but not in water, but the presence of water diminishes the risk of explosion. It begins to evaporate at 365° Fahr. It has been found that pure nitro-glycerine, dropped upon a thoroughly red hot iron, assumes a spheroidal state and flashes off into vapor in the same way as gunpowder; but if the iron is not red hot, only hot enough to cause the nitro-glycerine to boil suddenly, a frightful explosion takes place. The explosion of a single drop in this manner will cause serious damage. This dangerous compound requires most careful handling, a slight shock sometimes exploding it.

2143. To Prepare Nitro-glycerine

2143.     To Prepare Nitro-glycerine. Mix 100 parts fuming nitric acid at 50° Baume with 200 parts sulphuric acid; when cool, add 38 parts glycerine slowly, allowing it to trickle down the sides of the vessel. The glycerine will remain on the surface for hours without mixing. Stir the glycerine and acids with a glass rod for 10 seconds, pour it into 20 times its volume of water, and the nitroglycerine will be instantly precipitated to the extent of 76 parts, or double the amount of glycerine employed. It must be repeatedly washed with water, and then saturated with bicarbonate of soda or lime.

2144. Blasting Powders

2144.      Blasting Powders. Neither fresh nor salt water has any injurious effect on blasting powders; they need only to be dried to regain their explosive character. Their emitting but little smoke renders them useful in underground operations, and their explosive force is eight times that of gunpowder. They explode with extreme facility, either by contact with a strong acid, a slight elevation of temperature, or the slightest friction. In preparing them, therefore, excessive precaution is necessary, especially in mixing the ingredients. A straw, slightly wetted with oil of vitriol, applied to a small heap of the powder, will cause instantaneous explosion.

2145. To Make Blasting Powder

2145.     To Make Blasting Powder. Reduce separately to powder, 2 parts chlorate of potassa and 1 part red sulphuret of arsenic; mix very lightly together. Or: - Powder separately, 5 parts chlorate of potassa, 2 parts red sulphuret of arsenic, and 1 part ferrocyan-ide of potassium (prussiate of potassa); mix carefully. Or: - Mix carefully, as before, after having separately reduced to powder, equal parts chlorate of potassa and ferrocyanide of potassium.