RACK-A-ROCK.
This powerful explosive, composed of a solid and a liquid ingredient, entirely inexplosive when separate, but easily and quickly combined, seems to present undoubted advantages for use in the military service.
The solid is potassium chlorate, and the liquid is either "dead oil," or dead oil and bisulphide of carbon in equal volumes, or bisulphide of carbon with 3 per cent of carbon added, or mono-nitro-benzine.
General Abbot considered the following the best:
Potassium chlorate, 79 parts; mono-nitro-benzine, 21 parts.
The potassium chlorate is put up in the form of a cartridge enclosed in a bag made of cotton or other suitable material.
In preparing the charge for use the cartridges are placed in a wire frame, which is suspended from a spring-balance, and dipped in the liquid until a proportion of 3 to 4½ parts of solid to 1 part of liquid is shown by the balance; this requires from 3 to 6 seconds.
Or, place the cartridges in a pan containing cells (each cartridge having a corresponding cell and cup) and then pour in each cell its cupful of liquid. As soon as it has all been absorbed remove the cartridges and in ten minutes they are ready for use.
If the cartridges be kept, they appear to tend to increased sensibility to friction or percussion.