188 



SMITIISONIAX MISCELLANEOUS COLLECTIONS 



VOL. 54 



BARIUM. 



For the atomic weight of barium we have a series of seven ratios, estab- 

 lished by the labors of Berzelius, Turner, Struve, Marignac, Dumas, 

 Richards and Thorpe. Andrews ' and Salvetat/ in their papers u})on this 

 subject, gave no details nor weighings, and therefore their work may be 

 properly disregarded. First in order, we may consider the ratio between 

 silver and barium chloride, as determined by Pelouze, Marignac, Dumas 

 and Richards. 



Pelouze,' in 1845, made the three subjoined estimations of this ratio, 

 using his well known volumetric method. A quantity of pure silver was 

 dissolved in nitric acid, and the amount of barium chloride needed to 

 precipitate it was carefully ascertained. In the last column I give the 

 quantity of barium chloride proportional to 100 parts of silver: 



3.860 grm. BaCls ppt. 4.002 grm. Ag. 96.452 



5.790 " 6.003 " 96.452 



2.895 " 3.001 " 96.468 



Mean, 96.4573, 



.0036 



Hence Ba = 137.199. 



Essentially the same method was adopted by Marignac * in 1848. His 



experiments were made upon four samples of barium chloride, as follows : 



A, commercial barium chloride, purified by recrystallization from water. 



B, the same salt, calcined, redissolved in water, the solution saturated 

 with carbonic acid, filtered and allowed to crystallize. C, the preceding 

 salt, washed with alcohol and again recrystallized. D, the same, again 

 washed with alcohol. For 100 parts of silver the following quantities 

 of chloride were required, as given in the third column: 



1 Chemical Gazette, October, 1852. 



^Coinpt. Rend., 17, 318. 



8 Compt. Rend., 20, 1047. Joiirn. prakt. Chem., 35, 73. 



"Arch. Sci. Phys. Nat., S, 271. Oeuvres C«mplMes, ], 219. 



