and the Nature of Matter. 1 39 



that these conditions are in inverse proportions, for copper, 

 which contains nearly as many atoms as iron, conducts better 

 still than gold, and with above six times the power of iron. 

 Lead, which contains more atoms than gold, has only about 

 one-twelfth of its conducting power; lead, which is much 

 heavier than tin and much lighter than platina, has only 

 half the conducting power of either of these metals. And 

 all this happens amongst substances which we are bound to 

 consider, at present, as elementary or simple. Whichever way 

 we consider the particles of matter and the space between 

 them, and examine the assumed constitution of matter by this 

 table, the results are full of perplexity. 



Now let us take the case of potassium, a compact metallic 

 substance with excellent conducting powers, its oxide or hy- 

 drate a non-conductor; it will supply us with some facts ha- 

 ving very important bearings on the assumed atomic con- 

 struction of matter. 



When potassium is oxidized an atom of it combines with 

 an atom of oxygen to form an atom of potassa, and an atom 

 of potassa combines with an atom of water, consisting of two 

 atoms of oxygen and hydrogen, to form an atom of hydrate 

 of potassa, so that an atom of hydrate of potassa contains 

 four elementary atoms. The specific gravity of potassium is 

 0*865, and its atomic weight 40 ; the specific gravity of cast 

 hydrate of potassa, in such state of purity as I could obtain it, 

 I found to be nearly 2, its atomic weight 57. From these, 

 which may be taken as facts, the following strange conclusions 

 flow. A piece of potassium contains less potassium than an 

 equal piece of the potash formed by it and oxygen. We may 

 cast into potassium oxygen atom for atom, and then again 

 both oxygen and hydrogen in a twofold number of atoms, and 

 yet, with all these additions, the matter shall become less and 

 less, until it is not two-thirds of its original volume. If 

 a given bulk of potassium contains 45 atoms, the same bulk 

 of hydrate of potassa contains 70 atoms nearly of the metal 

 potassium, and besides that, 210 atoms more of oxygen and 

 hydrogen. In dealing with assumptions I must assume a little 

 more for the sake of making any kind of statement ; let 

 me therefore assume that in the hydrate of potassa the atoms 

 are all of one size and nearly touching each other, and that 

 in a cubic inch of that substance there are 2800 elementary 

 atoms of potassium, oxygen and hydrogen; take away 2100 

 atoms of oxygen and hydrogen, and the 700 atoms of potas- 

 sium remaining will swell into more than a cubic inch and a 

 half, and if we diminish the number until only those contain- 

 able in a cubic inch remain, we shall have 430, or thereabout. 



