Walter C. Holmes

Acid Fuchsin as a Stain—A Refinement in Manufacture

From the study of 38 samples of acid fuchsin prepared from several types of basic fuchsin and under varying conditions it is found that rosanilin sulfonated between 80° and 85°C. gives the best results in the Van Gieson staining technic. Staining tests also show that a satisfactory acid fuchsin will give the best results when employed with picric acid in the ratio of 1 part of the 1 per cent aqueous acid fuchsin to 20 parts of the aqueous picric acid. Details for the preparation and use of acid fuchsin are given.

The detonation wave from solid explosives

Abstract It has been shown that the detonation wave from a solid explosive changes in velocity after leaving the explosive. In the case of some low-velocity explosives, e.g., about 2400 metres per second, the velocity of the detonation wave increases by approximately 100–200 metres per second. With other high-velocity explosives, 5000–6000 m./sec., the velocity may decrease to around 4400 metres in some cases. Careful measurements have shown that a zone of uniform velocity exists beyond the surface of the explosive, the dimensions of the zone depending on the diameter of the sphere of the explosive or the diameter of the cartridge detonated. In the case of a 1 1 4 -inch dynamite cartridge, the zone of uniform velocity extended for about ten inches, while, with a sphere of explosive four inches in diameter, the zone extended for about 25 inches. An explanation of the reason for the high velocity of the detonation wave in the gaseous medium is suggested, linking it up with either the velocity of sound at the temperatures prevailing or the kinetic velocity of the gaseous particles themselves, the latter explanation appearing to be more in accordance with the determined facts. Such an explanation implies the assumption of extremely high momentary temperatures at the wave front, in some cases of over 40,000° C. These extremely high temperatures are due partly to the heat of combustion of the explosive ingredients but more to the heating effect resulting from the enormous pressures developed at the moment of explosion, as previously applied by Berthelot and Dixon in the study of gaseous explosions. Adiabatic conditions are assumed in such calculations. With such an explanation, reasonable agreement between theory and fact is obtained for a number of explosives, and the discrepancies that exist are in cases where discrepancies might be expected.