222 THE POPULAR SCIENCE MONTHLY, 



than from a heavy gun, "but the rock on which the canister lay was 

 broken into a thousand fragments. 



" This experiment strikingly illustrates the peculiar action of nitro- 

 glycerine. In using gunpowder for blasting, it is necessary to confine 

 it, by what is called tamping, in the hole prepared for it in the rock. 

 I^ot so with nitro-glycerine. This, though it may be put up in small 

 tin cartridges for convenience, is placed in the drill-holes without 

 tamping of any kind. Sometimes the liquid itself has been poured 

 into the hole, and then a little water poured on the top is the only 

 means used to confine it. As an agent for blasting, nitro-glycerine is 

 so vastly superior to gunpowder, that it must be regarded as one of 

 the most valuable discoveries of our age. Already it is enabling men 

 to open tracks for their iron roads through mountain-barriers, which, 

 a few years ago, it would have been thought impracticable to p)ierce, 

 and, although its introduction has been attended with such terrible 

 accidents, those best acquainted with the material believe that, with 

 proper care in its manufacture, and pro]3er precautions in its use, it 

 can be made as safe as or even safer than gunpowder, and the Govern- 

 ment can do no better service toward developing the resources of the 

 country than by carrying forward the experiments it has instituted at 

 the Torpedo Station at Newport, until all the conditions required for 

 the safe manufacture and use of this valuable agent are known, and, 

 when this result is reached, imposing on the manufacturers, dealers, 

 and carriers, such restrictions as the public safety requires. Of course, 

 we cannot expect thus to prevent all accidents. Great power in the 

 hands of ignorant or careless men implies great danger. Sleepless 

 vigilance is the condition under which we wield all the great powers 

 of modern civilization, and we cannot expect that the power of nitro- 

 glycerine will be any exception to the general rule. 



" But, while nitro-glycerine has such great rending power, it has 

 no value whatever as a projectile agent. Exploded in the chamber of 

 a gun, it would burst the breech before it started the ball. Indeed, 

 there is a great popular misapprehension in regard to the limit of the 

 projectile power of gunpowder, and inventors are constantly looking 

 for more powerful projectile agents as the means of obtaining increased 

 effects. But a study of the mechanical conditions of projection will 

 show not only that gunpowder is most admirably adapted to this use, 

 but also that its capabilities far exceed the strength of any known 

 material, and the student will soon be convinced that what is wanted 

 is not stronger powder, but stronger guns. I do not mean to say that 

 we cannot conceive of a better powder than that now in use, but 

 merely that its shortcoming is not want of strength. 



" In gunpowder the grains of charcoal and nitre, although very 

 small, have a sensible magnitude, and consist each of many thousand 

 if not of many million molecules. The chemical union of the oxygen 

 of the nitre with the carbon-atoms of the charcoal can take place only 



