IV PREFACE. 



manufacturer and practical experimentalist in the indications 

 which it gives of the properties and. powers likely to be 

 possessed by an explosive already made, or by one in con- 

 templation. 



Scores of useless and dangerous mixtures would never have 

 seen the light had the inventors known and profited by what 

 M. Berthelot has told us. 



Since the publication of M. Berthelot's work, new explosives 

 have come prominently on the scene both for military and civil 

 purposes. 



Perhaps the most noteworthy of these are the various so- 

 called " flameless " and " smokeless " explosives. To the first 

 of these belongs a group, whose main constituents are nitrate 

 of ammonium mixed with dinitrobenzol, or other nitro- 

 derivative of the benzol series. Such are Eoburite, Bellite, 

 Securite, and Ammonite, all of which are in use in this country 

 for blasting purposes, especially in fiery mines. To the second 

 class belongs the very numerous but not very varied group of 

 " smokeless " or quasi-smokeless powders. Of these, one or 

 another has been adopted by most nations for military purposes. 

 They are divisible into two distinct classes, viz. those which 

 consist of nitrocellulose as their main constituent, and those 

 which have not only nitrocellulose, but nitroglycerin as their 

 principal constituents. 



To these two classes they alf practically belong up to the 

 present time, though there are almost innumerable variations in 

 added ingredients or details of manufacture. By far the oldest 

 is the simple nitrocellulose powder. Some forms of it have been 

 widely used for many years in the sporting world. The older 

 powders, however, though excellent for shot-guns, failed in the 

 uniformity of result so essential in a military arm, and the diffi- 

 culties have been but comparatively recently overcome. 



The close attention which has been paid of late years to the 

 subject of explosives has not been without its effect on the 

 oldest of them. Gunpowder, not so very long ago a somewhat 

 haphazard mixture, has been made to take its place as an 

 explosive deserving and obtaining at least as much care in 

 its manufacture and treatment as the so-called " chemical 

 explosives." 



Picric acid, too, under various names and in various shapes, 

 has advanced from the rank of a u&eful article of ordinary 

 commerce to that of a powerful destructive agent. 



