44 On Hydrogenium. 



true alloy of hydrogenium, and whose white metallic aspect 

 is due alike to the hydrogenium and the palladium : it is 

 compressed into a space something less than the eight 

 thousandth part of that which it occupied as a gas, say at a 

 pressure of over eight thousand atmospheres, or of 123810 lbs. 

 per inch, or over 55 tons per inch. 



In this case we may, as 1 have said, set altogether aside 

 the idea of visible cavities or pores in the palladium, such as 

 fluids might pass through, as through a sieve or grating ; 

 for the chemist is cognisant of abundance of interspace 

 between the atoms of matter, spaces quite invisible to the 

 eye, even when aided by the most powerful microscopes, 

 but not less real on that account. And notwithstanding 

 all that is understood concerning the impenetrability of 

 matter, there appears to be quite an open road in the structure 

 of even the most dense solids, through which the atoms or 

 molecules of other kinds of matter can enter whenever 

 their chemical affinities dispose them for this kind of 

 interpenetration. 



In this way 23 parts of sodium, which is quite a solid 

 metal can absorb 24 parts of oxygen and 6 parts of carbon ; 

 considerably more than its own weight of these substances, 

 and the resulting carbonate of sodium occupies less space 

 than the original metal. Here is a sort of stereo- diagram 

 intended to show the composition of the chloride of 

 sodium contained in a gallon of sea-water ; it repre- 

 sents a sphere of sodium of something under 1.9 

 inches diameter, also a sphere of chlorine gas of over 

 •14| inches diameter. When, then, this relatively enor- 

 mous atmosphere of chlorine, weighing about one and 

 a-half times the weight of the sodium sphere is absorbed by 

 the latter, the resulting sphere of common salt (of rock salt 

 let us say) is but little larger than the original metallic sodium, 

 so great is the power of condensation due to the affinity of 

 the sodium for the chlorine, and so facile is the interpene- 

 tration of these constituent elements of the rock salt. But 

 in this latter example, although the condensation is so great, 

 there is, you will observe, a slight increase of bulk in the 

 product over that of the original metallic sodium. The 

 salt sphere measures nearly 2 inches diameter. 



The condensation of the hydrogen into the substance of 

 the palladium is also of the character of a chemical com- 

 bination, but the compound formed is an alloy of two metals 

 instead of a haloid salt. An enormous condensation takes 



