1S8 On the Chemical Constitution of 



gen, will be found to exhibit, in conformity to this view, a per- 

 fect coincidence with the law of proportions. One or two ex- 

 amples will be sufficient for illustration. 



Potassium, in the proportion of 100 with 20*5 of oxygen, con- 

 stitutes the binary compound denominated dry potash, and which 

 is probably the first degree of oxidation. If, in the ternary com- 

 pound, which constitutes the alkali in its common state, fused 

 potash as it is named, the additional portion of oxygen is equal 

 to this, or the whole quantity is twice that in the first, conform- 

 able to the usual law of proportions, then the quantity of water 

 which will be obtained from the subversion of its composition, 

 and which, according to the common doctrine, is water com- 

 bined with the alkali, will be 16 from 1,00 of the fused potash. 

 Now, Berthollet assigned the quantity from experiment at 14, 

 and Sir H. Davy at from 17 to 19. The mean of these may be 

 taken at 16, conformable, tlierefore, to the theoretical applica- 

 tion. And this q-aantity is stated on the authority of Berzelius 

 as the precise proportion. This second proportion of oxygen 

 seems to be established as an insulated binary compound in com- 

 bination with the radical, as well as in the ternary conibination 

 into which hydrogen also enters, if it is perfectly just, what has 

 been asserted, that the excess of oxygen in the product of the 

 combustion of potassium in oxygen is expelled by heat. And if 

 this compound were capable of being acted on by hydrogen, 

 (which it can scarcely be doubted it is,) it would afford another 

 ])erfect analogy to oxymuriatic acid, as by this action it would 

 be converted into potash, precisely as oxymuriatic acid is by the 

 same action converted into muriatic acid. The facility wich 

 which hydrogen is admitted into the binary compound, so as to 

 form the ternary combination, is still greater than the facility 

 with which a similar change is produced in oxymuriatic acid, the 

 addition of water alone producing the effect, converting the per- 

 oxide of potassium into potash, and liberating of course the cor- 

 responding excess of oxygen. 



Sodium combines with a larger quantity of oxygen than po- 

 tassium does; and therefore soda ought (adoi)tiu!; the language 

 of the common doctrine) to contain a larger quantity of com- 

 bined water, — the v, atcr being always proportional to a multij)!a 

 of the oxygen combined with the radical. The fact is accord- 

 ingly conformable to this, 100 of fused soda affording about 24 

 of water. 



Barium, on the contrary, combines with less oxygen. Sir 

 H. Davy, from indirect results, infers, that S9'7 of barium com- 

 bine with 10-3 of oxygen. In conformity to the law, therefore, 

 barvtes ought to afford less water, which is accordingly the case, 



100 



