140 Mr. Faraday on "Electric Conduction 



So a space which can contain 2800 atoms, and amongst them 

 700 of potassium itself, is found to be entirely filled by 430 

 atoms of potassium as they exist in the ordinary state of that 

 metal. Surely then, under the suppositions of the atomic 

 theory, the atoms of potassium must be very far apart in the 

 metal, /. c. there must be much more of space than of matter 

 in that body : yet it is an excellent conductor, and so space 

 must be a conductor; but then what becomes of shell-lac, sul- 

 phur, and all the insulators? for space must also by the theory 

 exist in them. 



Again, the volume which will contain 430 atoms of potas- 

 sium, and nothing else, whilst in the state of metal, will, when 

 that potassium is converted into nitre, contain very nearly the 

 same number of atoms of potassium, i. e. 416, and also then 

 seven times as many, or 2912 atoms of nitrogen and oxygen 

 besides. In carbonate of potassa the space which will con- 

 tain only the 430 atoms of potassium as metal, being entirely 

 filled by it, will, after the conversion, contain 256 atoms more 

 of potassium, making 686 atoms of that metal, and, in addi- 

 tion, 2744 atoms of oxygen and carbon. 



These and similar considerations might be extended through 

 compounds of sodium and other bodies with results equally 

 striking, and indeed still more so, when the relations of one 

 substance, as oxygen or sulphur, with different bodies are 

 brought into comparison. 



I am not ignorant that the mind is most powerfully drawn 

 by the phenomena of crystallization, chemistry and physics 

 generally, to the acknowledgement of centres of force. I feel 

 myself constrained, for the present hypothetically, to admit 

 them, and cannot do without them, but I feel great difficulty 

 in the conception of atoms of matter which in solids, fluids 

 and vapours are supposed to be more or less apart from each 

 other, with intervening space not occupied by atoms, and per- 

 ceive great contradictions in the conclusions which flow from 

 such a view. 



If we must assume at all, as indeed in a branch of know- 

 ledge like the present we can hardly help it, then the safest 

 course appears to be to assume as little as possible, and in that 

 respect the atoms of Boscovich appear to me to have a great 

 advantage over the more usual notion. His atoms, if I un- 

 derstand aright, are mere centres of forces or powers, not par- 

 ticles of matter, in which the powers themselves reside. If, 

 in the ordinary view of atoms, we call the particle of matter 

 away from the powers a, and the system of powers or forces 

 in and around it in, then in Boscovich's theory a disappears, or 

 is a mere mathematical point, whilst in the usual notion it is 



