Page:Popular Science Monthly Volume 3.djvu/670

652 percussion cap is fixed in the centre of this iron plate. The cartridge will hold 3 ounces of powder, with space for a thick felt wad between the latter and the projectile. The charge of powder employed at Satory was only 2 ounces, the unoccupied space being filled with two disks of brown paper, laid over the powder and covered with wadding. The shell, which has a total length of 2 calibres, has a jacket of latten covering a portion of its length, with grooves answering to the riflings of the gun. Its weight is 17 ounces, and it contains a charge of 1 ounce of powder. The whole cartridge, charged and primed, weighs 28 ounces.

The shell does not appear to be held tightly enough in the cartridge-case; it can be detached by the hand with but little trouble, and there is reason to fear lest, when charged cartridges are transported in boxes, the shells may be separated from their sockets.

To obviate all accidents, the revolver-cannon was set en batterie at about 100 metres, or 328 feet, from the butte, the shells being charged and provided with thin percussion fuses. At first the exploded cartridges, when withdrawn from the cannon, were not at once dropped by the extractor; but this slight defect was in a few minutes remedied, and, during the remainder of the experiments, there was no further difficulty in working the piece. The cartridges were greased before being used.

They suffered no injury from the discharge, and could be recharged and used over and over again. One had opened along the soldering, but had not been rent, nor had any gas escaped. It could be used again, on being soldered anew. Only one cartridge missed fire, and even this went off at the third trial. Only one of the shells also failed to explode. Nearly all of them went through the target, and only exploded in the butte. One, however, burst on striking the target, and one exploded within the gun-barrel; but this latter mishap is not necessarily to be attributed to any irregular action of its fuse, for the shells appear to have been badly cast, and one of the walls, oftentimes, by reason of the eccentricity of the central void, is extremely thin.

Six shots were fired in succession in 12 seconds, the cartridges being set in place one by one; then 15 cartridges in 15 seconds, with the use of boxes previously supplied with a certain number of cartridges. The fire might be kept up for some time at the rate of 60 shots per minute—equal to 66 pounds of cast-iron shot off in that space of time. The firing is very regular, and the sighting does not appear to undergo any notable variation.

Each shell breaks up into 12 or 15 fragments, large enough to produce mortal wounds at a certain distance from the point where they explode. Most commonly its bottom-piece (culot) separates from the rest without breaking, though lines of cleavage may have been made in it beforehand.

A notable drawback is the rapid fouling of the gun by the shells, which is manifest after the first few shots, and quickly grows worse. Doubtless this is attributable to the bad quality of the latten forming the jacket of the projectile.

We should say that the mechanism of Hotchkiss's revolving cannon works with certainty and regularity, and that its ammunition would do good service, were the shell better fastened in the cartridge. This shell is an article of difficult and delicate manufacture, and of a rather high price. The cannon would doubtless produce formidable effects at ranges approaching those of field-artillery, and the explosive properties of its projectiles give it a great advantage over all other mitrailleuses, since the aim can be regulated by observing the points where the shells fall.

Fertilization of Flowers.—Mr. Meehan last year exhibited, at the Philadelphia Academy of Natural Sciences, a pear having fibrous instead of granular flesh, and a tough rind like that of the apple. He accounted for these phenomena by the theory that apple-pollen had impregnated a pear-pistil. At the meeting of the Academy held January 21st he exhibited an ear of Indian-corn which serves to confirm his hypothesis. As soon as the "silk," that is, the pistils, appeared, the pollen in the "tassel" of a quite different variety of corn was set in a bottle near it, the plant's own tassel having been cut away some time previously. Soon this tassel was taken away, and replaced by