STRONTIUM. Ill 



slightly excessive weight of sodium chloride, and the excess 

 titrated with decimal silver solution. The mean result of 

 three experiments was that 100 Ag = 51.141 Na CI ; ex- 

 treme difference, 0.033. The value follows for Ag^ 

 1349.01; CI = 443.2. The sodium chloride was prepared 

 either from sodium sulphate and barium chloride, or from 

 sodium carbonate and chlorhydric acid, or from a very pure 

 rock salt. It was repeatedly recrystallized and was dried 

 at 200° or melted. {Paris Comptes Bend., W, 1845, 1047.) 



J. Dumas : 23.011 (O = 16). 



Determined from the mean of seven experiments on the 

 titration of sodium chloride with argentic nitrate ; extreme 

 difference, 0.09. Ag = 108 ; CI = 35.5 [Dumas gives the 

 mean as 23.014 instead of 23.0114.] For five experiments 

 Na CI recrystallized ten times and melted was employed. 

 For two experiments (giving an average of 23.036) the 

 residue from the incineration of the acetate was used to 

 prepare Na CI, which was recrystallized four times and 

 melted. [Annal. de Ghim. et de Phys., (3,) 66, 1859, 129.) 



J. S. Stas : 23.043 (O = 16). 



According to the mean of 10 determinations 100 Ag = 

 54.2078 Na CI; extreme difference 0.0033. The sodium 

 chloride was found to contain a minute quantity of silicic 

 acid which reduces the result from Na = 23.049 to 23.045 

 for Ag = 107.93; CI = 35.457. According to the mean of 

 five determinations 100 Na CI = 145.4526 sodium nitrate ; 

 extreme difference 0.025. If N = 14.044 this gives Na = 

 23.045. The lowest determination gives Na = 23.042. The 

 sodium chloride was purified by recrystallization and in part 

 by conversion into sodium chloroplatiijiate. The weighings 

 are for vacuum, {Stas, Untersuch. iiber Chem. Prop., Leip- 

 zig, 1867.) 



STRONTIUM. 



Regnault determined the specific heat of strontium chlo- 

 ride. It corresponds to an atomic weight of about 87.5. 

 {Gmelin-Kraut, I. c.) 



