328 



NA TURE 



[Feb. 6, 1890 



are now reduced to about 20,000, dispersed in small groups 

 over the islands of Luzon, Mindoro, Tablas, Panay, Negros, 

 Cebu, Paragan (Palawan), and Mindanao. A few [also appear 

 still to survive in Alabat, Busuanga, and Culiou. Of the Malay 

 peoples by far the most numerous and important are the southern 

 Bisayas (Visayas), and the northern Tagalas, both described as 

 "civilized Christians," and numbering respectively 1,700,000 

 and 1,250,000. These two peoples are steadily encroaching on 

 all the surrounding tribes, causing them to disappear by a 

 gradual process of absorption or assimilation, and the time is 

 approaching when the whole of the islands will be divided into 

 two great nationalities bearing somewhat the same relation to 

 each other that the High German does to the Low German 

 branch of the Teutonic family. 



SMOKELESS EXPLOSIVES.^ 



I. 



'T*HE production of smoke which attends the ignition or ex- 

 plosion of gunpowder is often a source of considerable in- 

 convenience in connection with its application to naval or 

 military purposes, its employment in mines, and its use by the 

 sportsman, although occasions not unfrequently arise during 

 naval and military operations when the shroud of smoke pro- 

 duced by musketry or artillery fire has proved of important 

 advantage to one or other, or to both, of the belligerents during 

 different periods of an engagement. 



Until within the last few years, however, but little, if any, 

 thought appears to have been given to the possibility of dispens- 

 ing with or greatly diminishing the production of smoke in the 

 application of fire-arms, excepting in connection with sport. 

 The inconvenience and disappointment often resulting from the 

 obscuring effects of a neighbouring gun-discharge, or of the first 

 shot from a double-barrel arm, led the sportsman to look hope- 

 fully to gun-cotton, directly after its first production in 1846, as a 

 probable source of greater comfort and brighter prospects in the 

 pursuit of his pastime and in his strivings for success. 



A comparison between the chemical changes attending the 

 burning, explosion, or metamorphosis of gun-cotton and of gun- 

 powder, serves to explain the cause of the production of smoke 

 in the latter case, and the reason of smokelessness in the case of 

 gun-cotton. Whilst the products of explosion of the latter con- 

 sist exclusively of gases, and of water which assumes the trans- 

 parent form of highly-heated vapour at the moment of its pro- 

 duction, the explosive substances classed as gunpowder, and 

 which consist of mixtures of saltpetre, or another nitrate of a 

 metal, with charred wood or other carbonized vegetable matter, 

 and with variable quantities of sulphur, furnish products, of 

 which very large proportions are not gaseous, even at high tem- 

 peratures. Upon the ignition of such a mixture, these products 

 are in part deposited in the form of a fused residue, which con- 

 stitutes the fouling in a fire-arm, and are in part distributed, in 

 an extremely fine state of division, through the gases and vapours 

 developed by the explosion, thus producing smoke. 



In the case of gunpowder of ordinary composition, the solid 

 products amount to over fifty per cent, by weight of the total 

 products of explosion, and the dense white smoke which it pro- 

 duces consists partly of extremely finely-divided potassium car- 

 bonate, which is a component of the solid products, and, to a 

 great extent, of potassium sulphate produced chiefly by the 

 burning of one of the important solid products of explosion — 

 potassium sulphide — when it is carried in a fine state of division 

 into the air by the rush of gas. 



With other explosives, which are also smoke-producing, the 

 formation of the smoke is due to the fact that one or other of the 

 products, although existing as vapour at the instant of its develop- 

 ment, is immediately condensed to a cloud composed of minute 

 liquid particles, or of vesicles, as in the case of mercury vapour 

 liberated upon the explosion of mercuric fulminate, or of the 

 aqueous vapour produced upon the ignition of a mixture of 

 ammonium nitrate and charcoal, or ammonium nitrate and picric 

 acid. 



Until within the last half-dozen years, the varieties of gun- 

 powder which have been applied to war purposes ia this and 

 other countries have exhibited comparatively few variations in 

 chemical composition. The proportions of charcoal, saltpetre, 



' Friday Evening Discourse delivered by Sir Frederick Abel, F.R.S., at 

 the Royal Institution of Great Britain, on January 31, 1890. 



and sulphur employed in their production exhibit slight differ- 

 ences in different countries, and these, as well as the character 

 of the charcoal used, its sources and method of production, 

 underwent but little modification for very many years. The 

 same remark applies to the nature of the successive operations 

 pursued in the manufacture of black powder for artillery purposes 

 in this and other countries. 



The replacement of smooth-bore guns by rifled artillery which 

 followed the Crimean war, and the increase in the size and power 

 of guns consequent upon the application of armour to ships and 

 forts, soon called for the pursuit of investigations having for their 

 object the attainment of means for variously modifying the action 

 of fired gunpowder, so as to render it suitable for the different 

 calibres of guns, whose full power could not be effectively, or in 

 some instances safely, developed by the use of the kind of gun- 

 powder previously employed indiscriminately in artillery of all 

 known calibres. 



In order to control the violence of explosion of gunpowder, by 

 modifying the rapidity of transmission of explosion from particle 

 to particle, or through the mass of each individual particle, of 

 which the charge of a gun is composed, the accomplishment of 

 the desired results was, in the first instance, and indeed through- 

 out practical investigations extending over many years, sought 

 exclusively in modifications of the size and form of the individual 

 masses composing a charge of powder, and of their density and 

 hardness, it being considered that, as the proportions of saltpetre, 

 charcoal, and sulphur generally employed in the production of 

 gunpowder very nearly correspond to those required for the 

 development of the greatest chemical energy by those incorporated 

 materials, it was advisable to seek for the attainment of the 

 desired results by modifications of the physical and mechanical 

 characters of, rather than by any modification in the proportions 

 and chemical characters of, its ingredients. 



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

 practical 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 iwo 

 distinct types. The first of these, produced by breaking up 

 more or less highly-pressed cakes of black powder into grains, 

 pebbles, or boulders, of approximately 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 granulated or corned powder, 

 represented by the old F, G., or small arms, and L. G., or 

 cannon powder. Gunpowder 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. R. L. G. (rifle large grain), which was the first step in 

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

 (P.), and large pebble 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, de- 

 mands 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 

 realization 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-perfora- 

 tions with the object of increasing the total inflaming surface of 

 the individual masses. 



Practical experience with this powder, and with others pre- 

 pared upon the same system, but with much less rigorous regard 

 to uniformity 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- 



