330 Dr. Thomson on the true Weiglit of [Nov 



Dalton is a multiple of 0"125, and both are too complex numbers 

 to be easily recalled to memory. 



My number for the atom of potash is 6. Mr. Dalton's number 

 exactly agrees with mine ; while both Wollaston's and Berze- 

 lius's are a very little less, and very nearly the same with each 

 other: 6 is a multiple of 0*125, for 0*125 x 48 = 6 ; but neither 

 the numbers of WoUaston nor of Berzelius are multiples of 0*125. 

 Berzelius's number is too long to be easily remembered. 



My number for the atom of muriatic acid is 4*625 ; for I con- 

 sider it to be demonstrated that it is composed of 1 atom of 

 chlorine = 4*5 + 1 atom of hydrogen = 0*125, making toge- 

 ther 4*625. The reasons for adopting these weights have been 

 given in a preceding essay on the specific gravity of the gases, 

 and they are such that I conceive no competent judge can enter- 

 tain any doubts respecting their accuracy. It would be needless 

 to compare the numbers of Dalton or Berzelius with mine. They 

 are derived from quite different principles, verjr comphcated, and 

 not multiples of 0*125. Dr. Wollaston's number is only a little 

 less than mine ; but neither is it a multiple of 0*125. My num- 

 ber is obviously a multiple, for 0*125 x 37 = 4*625. 



I propose now to demonstrate by an unexceptionable expe- 

 riment, which any person may repeat with the greatest ease, 

 that my numbers represent exactly the ratios of the weights of 

 the atoms of these four bodies. 



1 atom sulphuric acid % = 5 



1 atom potash = 6 



1 atom of sulphate of potash =11 



1 atom barytes = 9*75 



1 atom muriatic acid = 4*625 



1 atom muriate of barytes = 14*375 



When crystaUized muriate of barytes is exposed to a red heat 

 in a platinum crucible, it loses all its water of crystallization, 

 while at the same time the hydrogen of the muriatic acid unites 

 with the oxygen of the barytes, and flies off in the state of 

 water. The consequence is, that the muriate of barytes is 

 changed into chloride of barium. Now barytes is composed of 



Barium 8*75 



Oxygen 1*00 



9*75 

 And muriatic acid of 



Chlorine 4*5 



Hydrogen , 0*125 



4*625 



