\ 

 ▲TOMtC PRINCIPLEg OF CHEMISTRY. l4^ 



nJxidei nitrous gas, and nitric acid, according to the ex- 

 periments of Davy. And Dr. B. must confess, that the 

 greater part of the facts I have stated in my book, as the 

 g-rounds from which 1 draw my conclusions, are not new; 

 but facts that have been investigated by others before me, 

 and often with the same results; 



Dr. Bostock must be aware, that in writing my System^ 

 of Chemistry^ I have presumed all along, that the future 

 readers of it would be tolerably acquainted with the various 

 branches of the mechanical philosophy; otherwise I must 

 have made a cyclopedia of it; one department must have 

 treated of statics, another of dynamics, another of hydrody- 

 namics, another of pneumatics, &c. This was not my 

 design. If therefore I have announced certain rules as 

 proper to be laid down, and have given no demonstration 

 of them, it was because they were deemed obvious to the 

 class of 4"eaders I expected, or otherwise were such as could 

 not be demonstrated but by the gradual developement of 

 the system itself in its progres'*. 



I proceed now to point out the mechanical consistency Mechanical 

 of the Ist rule, which Dr. Bostock has quoted, page 283, consistency of 

 ,.,.,,, I u- *• r^ t r Mr. Dal ton's 



namely, that "when only one combination of two bodies ^^st rule of 

 can be obtained, it must be presumed to be a binary one, combinatioa. 

 unless some cause appear to the contrary" ; and if this be 

 established, the other three which he quotes may be consi- 

 dered as corollaries from it. 



Let us suppose a mixture, for instance, of hidrogenous Instance in tli« 

 and oxigenous gas, in such sort, that there are the same 0?^^^^"'^ 

 number of atoms of each gas; now as the gasses are uni- 

 formly diffused, each atom of hidrogea must have one of 

 oxigea more immediately in its vicinity. The atoms of 

 hidrogen are all repulsive of each other; so are those of ox- 

 igen : the atoms of hidrogen are all equally attractive of 

 those of oxigen, and the attraction increases in some un- 

 known ratio as the distance diminishes. Heat, or some 

 other power prevents the union of the two elements, till by 

 an electric spark, or some other stimulus, the equilibrium 

 is disturbed, when the power of affinity is enabled to over- 

 come the obstacles* to its efficiency, and a chemical union of 

 the elementary particles of hidrogen and oxigen ensues. 



Vol. XXIX,— June, 1811. L Now 



