NITROGEN BODIES OF MODERN CHEMISTRY. 217 



powder affords 300 cubic centimeters of gas, one gram of nitro-glycer- 

 ine developos 720 cubic centimeters. Moreover, tlie gun[)o\vder leaves, 

 theoretically, 43 per cent, of residuum, wbile uitro-giycerine leaves none 

 at all, for tbe large jiroportion of oxygen is so perfect a kindler for the 

 mass that it is changed altogether into gas. This gas contains 58 per 

 cent, carbonic acid, 20 per cent, watery vapor, 3^ per cent, oxygen, 18 J 

 l^ercent. nitrogen. 



Oxygen is seldom observed among the gases resulting from exi)losion, 

 and I do not think the oxygen found in this case is free ; it is probably 

 present as iiitroxyd gas, and still a compound which supports combus- 

 tion. The tremendous forceof nitro glycerine renders it tbe most energetic 

 servant in our mines, it divides our rocks, does all the work of blasting, 

 it is the Polyphemus of modern civilization — goes parallel with fearful 

 accidents. The slightest imprudence may provoke a terrible reaction; 

 and, moreover, it is a very capricious substance, which does not explode 

 as readily as gunpowder or gun-cotton ; occasiouiilly it burns away 

 quietly; on this account, ignorant people who have to do with it grow 

 more and more fearless, more and more careless, they disregard the 

 warnings of their overseers until at length tliey become foolhardy 

 and do something which arouses it from its indifference, when it explodes, 

 rending and destroying everything in its vicinity. The fact that the 

 liquid state of nitroglycerine causes it to leak and spread everywhere 

 led to attempts to produce it in a solid form, aiul the result of these 

 attempts is dynamite. This is merely a combination of nitro-glyceriue 

 with siliceous earth, containing a small quantity of oxide of iron,- which 

 tinges it yellow. This siliceous earth is the product of alga? of infusoria, 

 and of microi>hytes, and has a peculiar tubular structure. The tubules, 

 by reason of their capillarity, absorb the nitroglycerine, and hold it so 

 firmly tfiat it never becomes moist nor does it yield to light pressure or 

 friction ; therefore this form, dynamite, is comparatively harmless, and 

 has in some degree superseded the formidable explosive oil. Dynamite 

 explodes at 180°. An explosion in unconfined space is very different from 

 one that takes jdace under pressure. If I burn gun-cotton in the open 

 air the explosion is attended by no remarkable effect, because the air- 

 wavei8 equalize and convey away the shock ; but in a confined space the 

 explosion exerts its fracturing force on whatever is nearest. This, of 

 course, holds good of dynamite, and hence the inimerous accidents re- 

 sulting from careless handling ef the charges — I might say from the 

 utterly reckless use of dynamite. At first the untaught laborer is cow- 

 ardh^, too careful and fearful, when warned of danger by the experienced 

 overseer; by degrees he grows less vigilant, he begins to imagine that 

 the matter is not quite so serious, and finally, in some way, arouses this 

 malicious substance, and then the catastrophe takes place. 



It is to be hoped that this exi)losivecomi)ound will be in all cases manu- 

 factured at the place where it is to be used. The production of it is so 

 easy, success is so certain, that I do not comprehend why the hazard of 



