1890.] on Smokeless Explosives. 9 



The varieties of powder, which, as the outcome of careful practi- 

 cal and scientific researches in this direction, have been introduced 

 into artillery-service from time to time, and some of which, at any rate, 

 have proved fairly efficient, have been of two distinct types. The 

 first of these, produced by breaking up more or less highly-pressed 

 cakes of black powder into grains, j)ebbles, or boulders, of approxi- 

 mately uniform size and shape, the sharp edges and rough surfaces 

 being afterwards removed by attrition (reeling and glazing), are 

 simply a further development of one of the original forms of granu- 

 lated or corned powder, represented by the old F. G., or small-arms, 

 and L. G., or cannon-powder. Gunpowders of this class, ranging in 

 size from about 1000 pieces to the ounce, to about six pieces to the 

 pound, have been introduced into artillery-service, and certain of 

 them, viz. E. L. G. (rifle large grain), which was the first step in 

 advance upon the old cannon-powder (L. G.) ; pebble-powder (P), and 

 large j^ebble or boulder-powder (P 2), are still employed more or 

 less extensively in some guns of the present day. 



The other type of powder has no representative among the more 

 ancient varieties ; it has its origin in the obviously sound theoretical 

 view that uniformity in the results furnished by a particular powder, 

 when employed under like conditions, demands not merely identity 

 in regard to composition, but also identity in form, size, density, and 

 structure of the individual masses composing the charge used in a 

 gun. The practical realisation of this view should obviously be 

 attained, or at any rate approached, by submitting equal quantities of 

 one and the same mixture of ingredients, presented in the form of 

 powder of uniform fineness and dryness, to a uniform pressure for a 

 fixed period in moulds of uniform size, and under surrounding con- 

 ditions as nearly as possible alike. The fulfilment of these 

 conditions would, moreover, have to be supplemented by an equally 

 uniform course of proceeding in the subsequent drying and other 

 finishing processes to which the powder-masses would be submitted. 



The only form of powder, introduced into our artillery-service 

 for a brief period, in the production of which these conditions were 

 adhered to as closely as possible, was a so-called pellet powder, 

 which consisted of small cylinders, having semi-perforations with the 

 object of increasing the total inflaming surface of the individual 

 masses. 



Practical experience with this powder, and with others prepared 

 upon the same system, but with much less rigorous regard to uni- 

 formity in such details as state of division and condition of dryness 

 of the powder before its compression into cylindrical or other forms, 

 showed that uniformity in the ballistic properties of black powder 

 could be as well and even more readily secured by the thorough 

 blending or mixing together of batches presenting some variation in 

 regard to density, hardness, or other features, as by aiming at an 

 approach to absolute uniformity in the characters of each individual 

 mass composing a charge. 



