A NEW CONSTITUENT OF THE ATMOSPHERE, 215 
Mr. Crookes, who a short time ago called attention to the flame rising from platinum 
terminals, which convey a high tension alternating electric discharge, and pointed 
out its dependence. upon combustion of the nitrogen and oxygen of the air.* 
Mr. Crookes was kind enough to arrange an impromptu demonstration at his own 
house with a small alternating current plant, in which it appeared that the absorp- 
tion of mixed gas was at the rate of 500 cub. centims. per hour, or nearly 20 times 
as fast as with the battery. The arrangement is similar to that first described by 
SportiswoopE.t The primary of a RunmMKorrFr coil is connected directly with the 
alternator, no break or condenser being required; so that, in fact, the coil acts 
simply as a high potential transformer. When the arc is established the platinum 
terminals may be separated much beyond the initial striking distance. / 
The plant with which the large scale operations have been made consists of a 
De Menritens alternator, kindly lent by Professor J. J. THomson, and a gas engine. 
As transformer, one of SwinpurNe’s hedgehog pattern has been employed with 
success, but the ratio of transformation (24:1) is scarcely sufficient. A higher 
potential, although, perhaps, not more efficient, is more convenient. The striking 
distance is greater, and the arc is not so liable to go out. Accordingly most of the 
work to be described has been performed with transformers of the RuudMKoRFF type. 
The apparatus has been varied greatly, and it cannot be regarded as having even 
yet assumed a final form. But it will give a sufficient idea of the method if we 
describe an experiment in which a tolerably good account was kept of the air and 
oxygen employed. The working vessel was a glass flask, A (fig. 6), of about 1500 cub. 
centims. capacity, and stood, neck downwards, over a large jar of alkali, B. As in 
the small scale experiments, the leading-in wires were insulated by glass tubes, DD, 
suitably bent and carried through the liquid up the neck. For the greater part of 
the length iron wires were employed, but the internal extremities, EE, were of 
platinum, doubled upon itself at the terminals from which the discharge escaped. 
The glass protecting tubes must be carried up for some distance above the internal 
level of the liquid, but it is desirable that the arc itself should not be much raised 
above that level. A general idea of the disposition of the electrodes will be obtained 
from fig. 6. To ensure gas tightness the bends were occupied by mercury. A tube, 
C, for the supply or withdrawal of gas was carried in the same way through the 
neck. 
The RupnMKorrr employed in this operation was one of medium size. When the 
mixture was rightly proportioned and the arc of full length, the rate of absorption 
was about 700 cub. centims. per hour. A good deal of time is lost in starting, for, 
especially when there is soda on the platinums, the arc is liable to go out if lengthened 
prematurely. After seven days the total quantity of air let in amounted to 7925 cub. 
centims., and of oxygen (prepared from chlorate of potash) 9137 cub. centims. On 
* ‘Chemical News,’ vol. 65, p. 301, 1892. 
+ “A Mode of Exciting an Induction-coil.”’ ‘Phil. Mag.,’ vol. 8, p. 390, 1879. 
