18 On Sir II. Davifs Theory of Chlorine, &c. [JvLf, 



inches of hydrogen. Now -94225 of a grain of water are 

 capable of giving the gaseous form to either 3*769 grs. (mea- 

 suring 6-3027 inches) or 3*55609 grs. (measuring 5-94664 

 inches) of muriatic acid gas; and 5-8072 grs. of potash can 

 unite with the real acid contained in 2-9045 grs. or 4857 inches 

 of muriatic acid gas: so that the condensation could at most 

 amount to only either 11*1577. °r 10*80364 inches. If the 

 condensations were not independent of each other, the results 

 ought to have been 8*/ll7 gi's. of muriate of potash, 5-115 

 inches of hydrogen, *8645 of a grain of an-hydrous muriatic 

 acid, and 7'6973 inches of residual muriatic acid gas. 



Mr. Dalton has, in a subsequent part of his work,* joined 

 with the French chemists in supposing potassium to be a hydruret 

 of potash. He does not, however, look back to the reasoning 

 in page 290, to inquire whether, from the action of potassium 

 on muriatic acid gas, so much hydrogen be evolved, as might, 

 besides the quantity ascribed to the conversion of the potassium 

 into potash, leave a surplus to be accounted for from the decom- 

 position of the acid. It is probable that there is not : and this 

 probability will the better appear, if, for an instant, we admit 

 the truth of Mr. Dalton's atomic theory. In every binate com- 

 pound, the weights of the combined elements are proportional 

 to those of their atoms. Mr. Dalton has stated the weight of 

 the atom of hydrogen at 1, and that of potash at 42; of course, 

 that of hydruret of potash must be 43. The amount of the 

 hydrogen evolved in Sir H. Davy's first experiment, should 

 therefore have been T ' T of 8 grs. or '1860465 of a grain; a 

 quantity less than that noted by Sir H. Davy, by '0183675 of a 

 grain, or about *702 of a cubic inch; and falling short of the 

 result of calculation on the data of the experiment, by only 

 •52477 °f" a cubic inch. It is almost superfluous to say that this 

 slight discrepancy is not to be wondered at, in an investigation 

 which is as yet only in its infancy. Mr. Dalton, however, says 

 that water is a binate compound; therefore if 8 grs. of potassium 

 contain as many particles as '204411 of a grain of hydrogen, 

 and if the number of particles in this be equal to that contained 

 in 1-29152 gr. of oxygen, it follows that, in these quantities of 

 oxygen and of potassium, there exists an equal number of par- 

 ticles, and potash may be still an oxide of potassium. The hy- 

 drogen which appeared may of course have come entirely from 

 the water, without any decomposition of the acid.f 



• Pages 484—486. 



+ I would not be understood as having any reference here (o Mr. Murray"* 

 views of the nature of potassium; but merely as arguing against its being a 

 b)druret of pota-.li. 



(To is continued.) 



