The Power of Dynamite as illustrated by blasting exercises. (Translated from Freiheit by A. A.)

The efficiency of dynamite has so far shown its best at the various mechanical applications, such as at mining, at stone quarries, tunnel-blasting, &c., and it is for this reason, where proportional small quantities have worked wonders, that many believe in the possibility of blowing down strong brick walls with a mere handful of dynamite. Such persons, however, keep out of sight the main point of the question, i.e., that at the aforesaid mechanical operations the dynamite is closely confined in deep bores, with the bore-hole tightly stopped up, so that not one particle of power is wasted, while the dynamite operator at revolutionary jobs is in most cases compelled to place his explosive either outside of a wall, or at least, so that at any rate the greatest force of his charge is lost or wasted upon empty space. In some cases we admit that the revolutionary operator may get a chance to place his charge in a building so that it may be somewhat confined, such as in ventilation ducts in the walls, a chimney-hole, gas, heating, water or sewer pipes, either in or outside of the

wall. It must be remembered, however, that even if a charge is placed so it would have to be a very powerful one if the fall of the whole building should be expected to result from it. Far better it would be to place two or more charges at different points of the building. But what quantity then should be employed? Ten pounds of dynamite will destroy a common sized brick building completely, if manipulated rightly, But large and massive buildings, such as court houses, churches state capitols, &c., will require a charge of at least from forty to fifty pounds, if total ruin is intended, and the success is even then not assured, if the charge or several charges cannot be placed so that great loss of power is prevented. Where the necessity requires to operate at a strong building wholly from without a large quantity of explosives is required, inasmuch as the larger amount of force finding no immediate resistence, expands itself into free air, shattering doors and windows opposite the street. It is therefore useless to place dynamite on a window sill from the outside, because if the expansion of the explosive having room from all sides, it can certainly not test its power on the wall itself. If the explosive cannot be placed under or within the foundation wall of a building, it should, at least, be placed close to a main wall right above the ground, or better, a little underground. In such operations the

charge should not be packed in a very strong iron case, box, or cylinder, as is the case if its concussion should affect all sides around equally, like a bomb thrown between a crowd, but simple tin boxes or cases are by far the best, in order that no power may be wasted upon the iron casing, leaving its whole benefits to the wall to be destroyed. In the destruction of walls the cylinder form of packing dynamite is the best, and the longer the distance of wall to be destroyed the longer the cylinder must be; if possible several such cylinders should be combined through a fuse.

Following are some results of experiments by the Austrian war department in demolishing buildings with dynamite, which may also serve as a practical school for revolutionists;

A charge of four pounds of dynamite packed in a dice shaped tin box, placed against a brick wall of one foot six inches thickness, made a hole through the same two feet long and one foot six inches wide; a charge of seven pounds of dynamite packed in a similar box above mentioned, and placed against a brick wall of two feet thickness, created a breach of thirteen inches in length and fifteen inches wide. To cause a breach of five feet square in a brick wall of three feet thickness, 27 pounds of dynamite was required. On a wall of three feet and a half thickness, a charge of forty three pounds was tried. The result was a six feet wide

breach and a total caving in of the wall at the point of the explosion, stray bricks flying in the opposite direction to a distance of eighty feet.

More satisfactory results have been gained by loading down the dynamite charges with sand bags or eath, to save the loss of power. At the foot of a wall of one and a half feet thickness a dice shaped tin box with a charge of two pounds was sunk in the ground so that the top of the box came level with its surface. The box was then weighed down with a load of one and a half feet of ground on it. The explosion caused to the fall of the wall to a distance of nearly seven feet. A charge of five pounds of dynamite packed and placed as in the preceding case, though with a difference of using several bags of sand to weigh it down, and tried on a wall of two feet thickness created a breach of 28 inches wide and 31 long.

Another experiment was tried in the following manner: Two cylinders made of common tin, each being two feet long and having three inches diameter, were filled with seven pounds of dynamite each. These two cylinders were placed against the outside of a one and a half foot thick brick wall in a longitudinal manner so as to cover four feet of running space of the wall. The breach made by this 24 pounds of explosive was 6 and one half feet long by 7 feet wide.

The power of dynamite, however, can show up the best where its entire force can be applied upon the foundation of a wall as the following case will attest: At a four foot thick brick wall there were dug three holes seven feet deep, the distance between the holes being eight feet. A dice-shaped tin box filled with six pounds of dynamite were sunk in each hole and connected by a wire from an electric battery so that all three boxes could be exploded at the same time. The explosion caused the downfall of the wall to the extent of 25 feet in length. The holes of course having been filled up with earth after connecting the boxes to wire.

The above experiments were tried with dynamite of 75 per cent. strength. The materials recommended in the preceding article to manufacture dynamite will absorb three times their weight of pure nitro-glycerine, which will make dynamite of 75 per cent.

Comrade --- the manufacture of gun-cotton and glycerine gelatine which has lately been tried near Washington, D. C. with tremendous effect from large guns, will also be published. Of course we have no large expensive guns, but we can manufacture bombs of the same stuff which can be thrown from a sling.

In order to enable the reader to appreciate our preceding remarks concerning the effects of dynamite on its true merits,

it is necessary that a comparison be drawn between the latter and gun powder. Our resources concerning their points are the same from which we got the information about the effects of dynamite. They are taken from a publication of the war department of Austria which caused the different experiments to be made, of course, in the interest of civilization, i. e. in upholding their infamous system of brigandage. But we think that means by which such a system can be upheld are in nowise to be despised by the revolutionists as means to exerpate the same; and now to the point.

A charge of gun powder of sixty pounds packed in a tin box the same as dynamite was placed against a brick wall and exploded. The effect was exactly like zero, only the wall where the powder had lain became a little blackened. An injury of the wall could only be affected by the digging of deep holes at the wall in which the charge was placed and covered up to the level of the ground again. But even here the injury done the wall fell short as to a dynamite charge in proportions of about one to ten. Add to these the fact of the dynamite charges having been very much smaller than the powder charges here mentioned and the difference will appear enormous. As in times of war the destruction of bridges and other iron structures are of like importance as walls and buildings. We will give here also a few experiments. In

this line of work dynamite is especially an efficient agent of destruction, as the following experiment will attest:

A plate of rod-iron of two inches in thickness, six inches in width and six feet six inches in length, was fastened on a number of heavy posts rammed firmly in the ground. Upon this plate were laid two pounds of dynamite packed in a cyoinder of tin six inxhes long and two and three quarters of an inch in diameter. The explosion made a hole clean through the plate about the size of the cylinder. An iron single track railroad bridge, very formidably constructed and resting on piles eight feet apart, was the next object of testing dynamite. The charge contained twenty-six pounds and was packed in eight boxes of about equal weight. These eight boxes were packed one on top of the other and a little distance from one of the piers. The explosion brought down the whole structure. To destroy a railroad track the manipulation adopted was as follows: A blasting box (tin box) of a seven pound charge was placed on the ground close to a railroad track, right near a switch. The explosion caused one track to be thrown aside entirely, and caused the splintering of the other to about a foot distance, causing splinters of iron to fly a distance of three hundred yards. The nearest railroad ties were also destroyed. Cast iron bodies, however, are much easier acted upon by dynamite than articles of rod iron as the experiments of the following test

objects will prove:

A cast iron cylinder three feet eight inches long by a diameter of eleven and one half inches, the thickness of the solid iron having been one-half inch was totally demolished with a charge of twelve pounds of dynamite. A cast iron box of four feet seven inches by one foot and a half inches, the walls being three-quarters of an inch thick, was demolished with four pounds of dynamite. Another cast iron case of the dimension of seven feet three inches by thirteen inches by seven inches, was totally destroyed with six pounds charge.

To compare this experiment with the effect of gun powder there was placed on a plate of iron one-half inch thick, ten pounds of the latter explosive packed in a tin box. The effect was not only ridiculous, but there was none visible at all. On an iron plate of a tickness of a little over three quarters of an inch, twenty pounds of powder was exploded with no better results.

(to be continued).

NOTE.- In our nest issue we will give a description of dynamite bombs, gun cotton, fulminate of silver, and of mercury.

A. A.