768 GUNPOWDER 



dried. The sawdust is now ready to be treated with nitric acid. For this purpose a' 

 mixture of 40 parts strong nitric acid (1-48 to 1-50) is mixed with 100 parts of 

 sulphuric acid (1'84); and the mixture is allowed to stand two hours to cool. One 

 hundred parts of this mixture are then placed in an iron vessel, around which a stream 

 of cold water circulates, and six parts of the sawdust are gradually added, stirring all 

 the time. The sawdust is allowed to remain in the acid two or throe hours, the 

 stirring being continued. After this time the whole is transferred to a centrifugal 

 machine, and the acid separated. The wood is then washed for two or thrco days in 

 cold water, afterwards boiled in a weak soda solution, again well washed in cold 

 water, and then dried. It is now ready for the final operation, which consists in 

 soaking it for ten or fifteen minutes in a solution of 26 parts of nitrate of potash in 

 220 parts of water. After this it is carefully dried at a temperature not exceeding 

 44 C. ; the very fine dust is then separated by means of a drum sieve, and the 

 remainder is ready for market. ' Chem. Central Blatt.,' No. 44, p. 704. 



About six years since, M. Hochstadter made a comparatively safe application of 

 chlorate of potash to explosive purposes. Unsized paper was thoroughly soaked in, 

 and coated with, a thin paste consisting of chlorate of potash, finely-divided charcoal, 

 a small quantity of sulphide of antimony, and a little starch, gum, or some similar 

 binding material, water being used as the solvent and mixing agent. The paper was 

 rolled up very compactly, and dried in that form. In this manner very firm rolls of , 

 an explosive material are obtained, which burns with considerable violence in the 

 open air, and the propelling effect of which in small arms, has occasionally been 

 found greater than that of a corresponding charge of rifle-powder. Moreover, the 

 material, if submitted in small portions to violent percussion, exhibits but little 

 tendency to detonation. But as no reliance can be placed on a sufficiently uniform 

 action of these explosive rolls in a fire-arm, this alone sufficed to prevent their com- 

 peting with powder. The same description of explosive preparation, differing only 

 from that of Hochstadter in a trifling modification of its composition, has recently been 

 brought forward in this country by M. Reichen and Mr. Melland. 



An explosive composition was patented in this country, in which spent tan broken 

 into small fragments was saturated with the oxidising agents, nitrate and chlorate of 

 potash, and then dusted over with sulphur. This composition deflagrates slowly when 

 ignited in the open air, but when confined in blast holes it exhibits sufficient explosive 

 force to do good work. See Abel's Lecture ' On Recent Progress in the History of 

 Proposed Substitutes for Gunpowder,' Royal Institution, May 4, 1866, and Watts's 

 Dictionary of Chemistry.' 



Gunpowder rendered non-explosive : Mr. Gale's Patent. The rapidity of burning of 

 gunpowder which is only another name for its degree of explosiveness depends, 

 cceteris paribus, upon the facility afforded to the propagation through the mass of the 

 heated gases generated by the first ignited portion. The requisite facility is afforded 

 in ordinary gunpowder by breaking it up into grains, thus creating a number of 

 crevices through which the gases can pass from grain to grain with a rapidity pro- 

 portioned to the size and number of the interstices. Mr. Gale's process which is not, 

 we believe, employed in any country consisted merely in filling up these crevices 

 with finely-powdered glass or other suitable substances, thus shutting off the com- 

 munication between the grains, and destroying the explosive character of the powder. 

 He diluted the powder with so much incombustible dust as may bo required to prevent 

 the gunpowder from burning ; and he restored its explosive character by simply sifting 

 out the diluent and once more opening the pores of the powder. 



Considering that nobody acquainted with the nature of gunpowder was ignorant 

 of the simple facts upon which Mr. Gale's process was based, and that these facts were 

 experimentally proved on a large scale by M. Piobert as far back as 1835, and by the 

 Russian chemist Fadeieff between 1841-4 ; that the results of those experiments are 

 detailed in Piobert's Traite tfArtilleric, and that similar experiments have been made 

 more recently in this country, Mr. Gale could hardly claim for this proposition the 

 originality which was at first popularly supposed to attach to it. Indeed, it seems 

 that his process differed from that of Piobert and Fadeieff only in the employment of 

 a different quality and larger quantity of protective powder. But the question of the 

 probable value of the process is distinct from that of its originality. While hesitating 

 to pronounce an opinion as to its possible occasional value for the storage of merchants' 

 or mining powder, wo may confidently assert what we believe to be the opinion of the 

 majority of naval and military men, that for military purposes or for the treatment of 

 powder on board our ships of war, the discovery had no practical value. It was at once 

 open to the very definite objection that it entailed an increase of .storage room to thrco 

 and a half times that ordinarily required, while the transport of so much additional 

 deadweight, whether on sea or on land, was regarded as absolutely impractionMc. 

 Such experiments as were made, moreover, exhibited a decided tendency to unmix 



