50 



SIXTH RKPORT. 1836. 



phate a,nd lime water. Both precipitates are white when dried as much 

 as possible at a low temperature ; but that from the pyrophosphate 

 becomes black if exposed to a red heat, while the other by the same 

 treatment retains its whiteness. 



W hen in the course of these experiments crystals were the subject of 

 operation, Mr. Watson took care to use such as were neither damp nor 

 effloresced. To manage this he powdered a quantity of large crystals, 

 and then intimately mixed them with so much Avater as rendered them 

 decidedly damp ; he then spread them very thinly over a flat surface in 

 a room where the force of vapour in the atmosphere was not so much as 

 0"15 of an inch of mercury less than it would have been if the atmo- 

 sphere was saturated with vapour, and left them in that state until they 

 discontinued to lose weight, an atmosphere of this diying power being 

 incapable of depriving the salt of any of its water of crystallization. 



Extracts from a Paper " on Important Facts obtained Mathemutically from 



Theory, embracing most of those experimental results in Chemistry, 



which are considered as ultimate facts ." By Thomas Exley, A.M. 



Mr. Exley observed that his object was to place chemistry under the 



domain of mathematical science, and to establish a new theory by 



legitimate but easy calculations. 



^ The principles of the theory are : 1. That every atom of matter con. 

 sistsof an indefinitely extended sphere offeree, varying inversely as the 

 square of the distance from the centre ; 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 centre and is called re- 

 pulsion. 



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

 their absolute forces, or in the radii of their spheres of repulsion, or in 

 both these. 



The attraction is the same as that of gravitation in the theory of 

 Newton or that of Boscovich ; but in both these theories, where gravita- 

 tion ends a series of alternations of attraction and repulsion varying by 

 unknown laws commences; Newton closes with a solid, Boscovich with 

 a sphere of repulsion varying inversely as the distance. Mr. Exley con- 

 siders that his theory differs in every particular from both these in the 

 spaces where chemistry and its connate sciences are concerned, and 

 does not like them launch into the regions of conjecture. 



The first principle, as far as regards the attraction, is really true in 

 nature ; nothing in jjhysics is better established. It is equally certain 

 from jjh^nomena that there is some repulsion near the centre of atoms ; 

 the law of its vaiiation has not been determined, but the order of na- 

 ture, the inductive procedure, obliges us, in the absence of every con- 

 tradictory pheenomenon, to continue the law of gravitation. As well may 

 we contend that there is no force of gravitation in spaces where no 

 particular observaticns have been made, as to say that the same force 

 does not exist in the sphere of repulsion, in tlie law of force — in the 

 quantity of force, there is no violation of the law of continuity ; the di- 

 rection only changes jier saltum, which is quite as easy to conceive as a 



