238 
POPULAR SCIENCE REYIEW. 
inches) ; it measuring, when charged, 618*923 millims. The 
density of the charged wire is reduced from 12*3 to 11*79. 
The e:^^pulsion of hydrogen from the wire, however caused, is 
attended with an extraordinary contraction of the latter. On 
expelling the hydrogen by a moderate heat, the wire not only 
receded to its original length, but fell as much below that zero 
as it had previously risen above it. That a very remarkable 
change is produced in the palladium by the absorption of the 
hydrogen is shown by the manner in which it burns. A wire 
so charged with hydrogen, if rubbed with the powder of mag- 
nesia (to make the flame luminous), burns like a waxed thread 
when ignited in the flame of a lamp. It has been proved that the 
tenacity of palladium is altered by the occlusion of hydrogen. 
The tenacity of palladium wire being 100, the tenacity of 
palladium and hydrogen was found to be 81*29. 
Dr. Faraday determined, by many experiments, that palladium 
is “ feebly but truly magnetic,” and he placed this element at 
the head of what are now called paramagnetic metals. The 
experiments of Mr. G-raham show that, with occluded hydrogen, 
palladium becomes so magnetic that it must be allowed to rise 
out of the paramagnetic class, and to take place in the strictly 
magnetic group with iron, nickel, cobalt, chromium, and man- 
ganese. Many chemical peculiarities distinguish this compound 
from ordinary palladium. The conclusions which appear to 
flow from this enquiry are, that in palladium fully charged with 
hydrogen there exists a compound of palladium and hydrogen 
in a proportion which may approach to equal equivalents. The 
charged palladium is represented by weight as 
ralladium . . 1‘0020 grm . 99-277 
Hydrogen . . 0*0073 grm . *723 
100^00 
It is in the proportion of one equivalent of palladium to 
0*772 equivalent of hydrogen H= 1, Pci = 106*5. The evidence 
is therefore strong that a true alloy is produced, and to this 
alloy the name of Hydrogeniam has been given. 
In this alloy hydrogen appears to be reduced to the metallic 
state, and the great problem of the chemist, as it regarded the 
physical condition of hydrogen, is satisfactorily solved. The 
magnetic character of this alloy may have its bearing upon the 
appearance of hydrogeniiim in meteoric iron, in association with 
certain other magnetic elements. 
The absorption of hydrogen by palladium is a striking fact. 
That this gas is absorbed by platinum and by iron has also 
])cen proved. The occluded hydrogen found in meteorites 
points to a condition in space, upon which we can only ob- 
scurely speculate. Spectrum analysis is teaching us that this 
