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 nitroglycerine. 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. Not 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 pierce, 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 proper precautions in its use, it can be made as safe as or even safer than gunpowder, and the Government 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
