182].] Atomic Weight of various Metals and Acids. 133 



pound of 2 75 boracic acid and 8 soda, or of 1 atom boracic acid 

 and 2 atoms soda. As for the watery constituent, it is not so 

 well made out, though we can scarcely hesitate to admit that it 

 amounts to just eight atoms. Borax then is composed of 



1 atom boracic acid = 2-75 



2 atoms soda 8*0 



8 atoms water 9 



19-75 



So that an integrant particle of it weighs 19-75. 



4. To verify this composition, I dissolved 19*75 grs. of crystal- 

 lized borax in distilled water, and neutralized the soda by means 

 of acetic acid. To get rid of any excess of acetic acid, 1 evapo- 

 rated the liquid to dryness, and redissolved the residuum in 

 water : 13 25 grains of chloride of barium were likewise dis- 

 solved in water, and the two solutions were mixed. It is 

 evident that the 19-75 grains of borax contained (if my analysis 

 was correct) exactly 2-75, or one atom of boracic acid; while 

 13-25 grains of chloride of barium, when dissolved in water, 

 contain 9*75 grains, or one atom of barytes. Now as borate of 

 barytes is an insoluble salt, I expected a double decomposition 

 to have taken place, and that the whole borate of barytes would 

 have precipitated, leaving the clear liquid incapable of being 

 rendered muddy by muriate of barytes, sulphate of soda, or 

 sulphuric acid. The result, however, was different. No preci- 

 pitate whatever appeared, indicating that no decomposition had 

 taken place. I, therefore, evaporated the whole to dryness, 

 poured water on the dry residue, and after digesting for some 

 time, poured it on a filter; there remained on the filter five 

 grains of borate of barytes. The clear liquid which passed 

 through the filter being evaporated to dryness, digested in water, 

 and again filtered, left 7-1 grains of the same borate of barytes: 

 The residua! liquid was a third time evaporated to dryness, and 

 treated as before ; 03 gr. of borate of barytes were obtained. I 

 repeated this process a fourth time, but could procure no more 

 borate of barytes. Thus the whole borate of barytes obtained 

 was : 



Grains. 



By first filtration 5-0 



By second filtration 7-1 



By third filtration 0-3 



l¥i 



Now if the 19-75 grs. of borax contained 2-75 grs. of boracic 

 acid, and the 13'25 grs. of chloride of barium yield 9-75 grs. of 

 barytes, it is obvious that the whole borate of barytes ought to 

 have been 12-5 grs.; so that in the preceding experiment there 

 seems to have been a loss sustained amounting to 0- 1 gr. or less 



