124 MEETING OF THE BRITISH ASSOCIATION 



nished the components. Some differences of opinion arose on the 

 subject. 



Tuesday. — The first subject to which the chairman called the 

 attention of the section was a paper by Mr. Thomas Exley, A.M., 

 on rendering chemistry a mathematical science. The paper is en- 

 titled " Important Facts obtained mathematically from theory, em- 

 bracing most of those Experimental Results in Chemistry which 

 are considered as Ultimate Facts." Mr. Exley observed: — His 

 object was to place chemistry under the domain of mathematical sci- 

 ence, and to establish his new theory by legitimate but very easy 

 calculations. The principles on which the whole theory rests are — 



1. That every atom of matter consists of an indefinitely extended sphere 

 of force, which varies inversely as the square of the distance from the cen- 

 tre ; and that this force acts towards the centre, and is called attraction at all 

 distances, except in a small concentric sphere, in which it acts from the cen- 

 tre, and is called repulsion. 



2. That there is a difference in atoms, arising from a difference in their 

 absolute forces, or the radii of their spheres of repulsion, or from both these. 



Three classes of atoms were noticed — tenacious, electric, and 

 etherial atoms. In respect of the attraction in the first principle, 

 this theory agrees exactly with the theories of Newton and Bosco- 

 vich, but after that, where chemistry and its connate sciences are 

 concerned, they are unlike in every particular. It was shewn that 

 the atomic weight of hydrogen being taken equal one, as the unit 

 of comparison, that of oxygen should be sixteen, instead of eight, as 

 used by the British chemists. One of the arguments was drawn 

 from the analogous composition of sulphurous and carbonic acids, 

 concerning which both sides are agreed, and steam and sulphuretted 

 hydrogen, concerning which they differ. 



1. Sulphurous acid is the sole gaseous product when sulphur is burnt in 

 dry oxygen gas, and the resulting volume is the same as that of the oxygen 

 consumed. 



2. Carbonic acid is the sole gaseous product when carbon is burnt in oxy- 

 gen gas, and the resulting volume is the same as that of the oxygen con- 

 sumed. 



3. Steam is the sole gaseous product when oxygen is burnt in hydrogen 

 gas, and the resulting volume is the same as that of the hydrogen consumed. 



4. Sulphuretted hydrogen is the sole gaseous product when sulphur is 

 burnt in hydrogen gas, and the resulting volume is the same as that of the 

 hydrogen consumed. 



These exact analogies, with others, shew clearly that they agree 

 in composition. But all parties allow that each of the first two 

 contains three atoms ; therefore we ought to conclude each of the 

 others contains three atoms : therefore sixteen is the atomic weight 

 of oxygen. Other equally cogent arguments were advanced. It 

 was also shewn, by ten striking examples, that 12, the atomic 

 weight of carbon, as determined by Dr. Thompson, is nearer the 

 truth than 12.25, as given by Berzelius. The following proposi- 

 tions were demonstrated : — 



