190 NOTICE OF SCHOENBEIN. 



occuiTence of several severe accidents during its production, attended with great 

 loss of lite, caused it to be regarded as too dangerous for military purposes, and, 

 accordingly, its manufacture was foi" a time almost abandoned. Within the last 

 few years, however, the attempt to make use of it as a substitute for gunpowder 

 has been renewed and l>rought to a successful issue by an Austi'ian officer of 

 artillery. 



Gun-cotton is used in military operations in the form of a spun yarn, in which 

 it conducts combustion slowly in the open air at a rate of not more than one 

 foot per second. Tliis yarn is used to form cartridges for large guns, by being 

 wound round a bobbin, so as to form a hollow spindle and thus give an interior 

 surface for the action of the flame and the production of the most effective explo- 

 sion. The effect of the explosion of gun-cotton under water is remarkable ; the 

 action is so instantaneous that the water has no time to yield, and consequently 

 transmits the impulse as a solid material ; hence it is unnecessary to place the 

 charge in immediate contact with the body to be destroyed. In one experiment 

 two parallel rows of piers, 10 inches thick, in water 13 feet deep, with stones 

 between them, were blown to pieces by a baiTel of 100 pounds of gun-cotton, 

 placed at a distance of three feet from one side and eight feet under water. It 

 made a breach of 15 feet, and threw the water to a height of 200 feet. In another 

 experiment with 400 pounds of gun-cotton a vessel was blown up, the pieces pro- 

 jected into the air to a height of 400 feet, and the fishes for nearl}^ half a mile 

 around were so stunned as to float on the Avater. The rapidity of expansion and 

 great elastic force of gun-cotton renders it a valuable agent in blasting. Its 

 power when exerted against a great resistance, as in the case of splitting a rock, 

 when compared with that of gunpowder, is in the ratio of 6^ to 1. 



The discovery which has rendered the name of Schoenbein most extensively 

 known is that of ozone. Before the end of the last century Van Marum, of Hol- 

 land, had observed that when an electric discharge was passed through oxygen 

 the latter acquired a peculiar smell and the power of attacking mercury, l)at it 

 was not until 1840 that any notice was taken of these facts, when Schoenbein 

 published his first paper on ozone. In this he announced the fact that in the 

 decomposition of Avater, by means of a galvanic battery, an odorous gas was given 

 off at the positive pole, and that this might be preserved for a long time in a 

 well-closed vessel. He also pointed out the fact of the similarity of this odor to 

 that which accompanies a discharge of electricity, especially from points, and 

 also the slow oxidation of phosphorus. Opinions as to the cause of the odor 

 were long divided, but through the experiments of Schoenbein and the investi- 

 gations of Andrews, and Tait, and others, it is now generally refeiTed to oxygen 

 in a changed or allotropic condition. 



One of the simplest methods of exhibiting the production of ozone consists in 

 transmitting a current of oxygen through a glass tube, into the sides of which a 

 pair of platinum wires have been sealed, with their points a small distance apart. 

 On connecting one of these wires with the prime conductor of an electric machine, 

 in active operation, while the other is connected with the ground, the odor of 

 ozone is immediately perceptible in the stream of gas. But in order to produce 

 a maximum effect it is necessary to transmit the discharge silently in the form of 

 a brush or a star, since sparks appear to produce an opposite effect, and are, 

 therefore, to be avoided. Ozonized air may also be obtained by placing a stick 

 of clean, moist phosphorus in a bottle of air or oxygen, when, after an hour or 

 so, the smell of ozone will be obvious. The stick of phosphorus is then to be 

 taken out and the gas washed with water to remove the phosphorous acid. Or 

 ozone may at once be produced by plunging a heated glass rod into a mixture 

 of air and a vapor of ether. The galvanic decomposition of water acidulated 

 Avith sulphuric acid, or better, perhaps, Avith the addition of chromic acid, affords 

 at the positive pole a large supply of ozone. The general characteristics of 

 ozone are those of an oxydizing agent j it corrodes organic matter, as shown in 



