154 HYDROGENIUM; THE RELATION OF HYDROGEN TO PALLADIUM. 
“ 1. The lamp being hermetically sealed, and there being no connection whatever be¬ 
tween the air inside the lamp and the air in the mine, no explosion could possibly 
occur. In the case of Mr. Bessemer’s lamp, in spite of the current of air leaving the lamp, 
traces of the atmosphere of the mine would certainly find their way into the lamp, and 
should any cause, even for the fraction of a second, interfere with the current, the lamp 
would become charged with the atmosphere of the mine, and on being relighted an ex¬ 
plosion might occur. 
« 2. It would give any amount of light that might be desired. 
“ 3. As one lamp hung up in a proper place would illuminate an entire set of work¬ 
ings, each miner would not, as at present, be hampered by carrying a small, flickering, 
troublesome, dangerous lamp, hardly able to do more than just render darkness visible. 
HYDROGENIUM; THE RELATION OF HYDROGEN TO PALLADIUM. 
{Concluded from p. 80.) 
4. Magnetism .—It is given by Faraday as the result of all his experiments, that pal¬ 
ladium is “feebly but truly magnetic and this element he placed at the head of what 
are now called the paramagnetic metals. But the feeble magnetism of palladium did not 
extend to its salts. In repeating such experiments, a horseshoe electro-magnet of soft 
iron, about 15 centims. (6 inches) in height, was made use of. It was capable of sup¬ 
porting 60 kilogs., when excited by four large Bunsen cells. This is an induced magnet 
of very moderate power. The instrument was placed with its poles directed upwards ; 
and each of these was provided with a small square block of soft iron terminating late¬ 
rally in a point, like a small anvil. The palladium under examination was suspended 
between these points in a stirrup of paper attached to three fibres of cocoon silk, 3 de¬ 
cimetres in length, and the whole was covered by a bell glass. A filament of glass was 
attached to the paper, and moved as an index on a circle of paper on the glass shade 
divided into degrees. The metal, which was an oblong fragment of electro-deposited 
palladium, about S millims. in length and 3 millims. in width, being at rest in an equa¬ 
torial position (that is, with its ends averted from the poles of the electromagnet), the 
magnet was then charged by connecting it with the electrical battery. The palladium 
wars deflected slightly from the equatorial line by 10° only, the magnetism acting against 
the torsion of the silk suspending thread. The same palladium charged with 604-0 
volumes of hydrogen was deflected by the electromagnet through 48°, when it set itself 
at rest. The gas being afterwards extracted, and the palladium placed equatorially be¬ 
tween the poles, it was not deflected in the least perceptible degree. The addition of 
hydrogen adds manifestly, therefore, to the small natural magnetism of the palladium. 
To have some terms of comparison, the same little mass of electro-deposited palladium 
was steeped in a solution of nickel, of specific gravity 1-082, which is known to be mag¬ 
netic. The deflection under the magnet was now 35°, or less than with hydrogen. The 
same palladium being afterwards washed and impregnated with a solution of protosul¬ 
phate of iron of specific gravity l - 048, of which the metallic mass held 2 3 per cent, of 
its weight, the palladium gave a deflection of 50°, or nearly the same as with hvdrogen. 
With a stronger solution of the same salt, of specific gravity 1*17, the deflection was 90 , 
and the palladium pointed axially. 
Palladium in the form of wire or foil gave no deflection when placed in the same ap¬ 
paratus, of which the moderate sensitiveness was rather an advantage in present circum¬ 
stances ; but when afterwards charged with hydrogen, the palladium uniformly gave a 
sensible deflection of about 20°. A previous washing of the wire or foil with hydro¬ 
chloric acid, to remove any possible traces of iron, did not modify this result. Palladium 
reduced from the cyanide and also precipitated by hypophosphorous acid, when placed 
in a small glass tube, was found to be not sensibly magnetic by our test; but it always 
acquired a sensible magnetism when charged with hydrogen. 
It appears to follow that hydrogenium is magnetic, a property which is confined to 
metals and their compounds. This magnetism is not perceptible in hydrogen gas, which 
was placed both by Faraday and by M. E. Becquerel at the bottom of the list of dia¬ 
magnetic substances. This gas is allowed to be upon the turning-point between the 
