112 ATOMIC WEIGHT DETERMINATIONS. 



M. H. Klaproth ; F. H. Wollaston : 9J^.I^. (O = 16) ; 

 590 (0 = 100). 



Klaproth found 42 sulphuric anhydride = 58 strontium 

 oxide; whence the value for 8 = 200. (PM. Trans. ^ 104; 

 1814, 20.) 



F. Stromeyer ; 87.34. (O = 16) ; 545.929 (0 = 100). 



According to Berzelius, Stromeyer found that 100 stron- 

 tium chloride = 181.25 argentic chloride; whence the value, 

 for Ag = 1349.66; CI = 221.64. {Berzelius' Lehrbuch, 3, 

 1229.) In Gilberfs Ami., 54, 1816, 251, Stromeyer refers to 

 this analysis as by V. Rose. Stromeyer himself found 0.5 

 grm. carbonate = 75.5394 c. c. carbon di-oxide [which 

 gives Sr := 88.26 if 1000 c. c. carbon di-oxide weigh 

 1.96433 grm.] Stromeyer calculated Sr = 552.28 for O = 

 100. 



— . Salvetat: 88 (0 = 16); 550 (0 = 100). 



Determined from the loss of weight of strontium carbo- 

 nate by calcination and on driving off carbon di-oxide with 

 sulphuric acid. Details not given. {Paris Comptes Rend., 

 17, 1843, 318.) 



J. Pelouze : 87.68 (O = 16) ; 548.02 (0 = 100). 



A known weight of perfectly pure silver was brought in 

 contact with a known and slightly excessive amount of 

 strontium chloride and the exce'ss titrated with decimal 

 silver solution. The number is the mean of two experi- 

 ments; extreme difference, 0.2. Ag = 1349.01; CI = 

 443.2. The chloride was purified by recrystallization and 

 was dried at 200° or below redness. {Paris Comptes Bend., 

 W, 1047.) 



C. Marignac : 87.54 (0 = 16). 



Marignac made experiments on three different prepara- 

 tions of strontium chloride, (1,) (2,) (3.) Compared with 

 silver by Pelouze's method it was found that ten grammes 

 strontium chloride = (1) 8.103; (2)8.099; (3) 8.101 silver. 

 The same strontium chloride converted into sulphate gave 

 (1) 6.887; (2) 6.8855; (3)6.884 sulphate. In both these 

 series of experiments the strontium was weighed as air- 

 dried, hydrous, crystalline chloride. Comparison gives Sr 



