140 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 54 



From ratios 12, 19, and Ag Br = 79.8600, ± .0101 



" 3, 22, 38, and Ag 79.9008, ± .0011 



" 15 and Ag 79.9177, ± .00038 



" 17, Ag, and CI 79.9189, ± .00063 



" 1, 3, 35, and Ag 79.9353, ± .00079 



" 3, 11, 23, 38, and Ag 79.9555, ± .0085 



" 1, 2, 3, 50, and Ag 79.9775, ± .0133 



11 and Ag 80.0040, ± .0134 



" 1, 2, 3, 49, and Ag 80.0624, ± .0054 



" 3, 8, and 38 80.1320, ± .0597 



" 8, 23, and Ag 80.2910, ± .0940 



General mean, Br = 79.9197, 



.0003 



From Baxter^s measurement of the silver bromine ratio, when Ag: 

 107.88, Br= 79.916. The difference is less than 1 part in 21,000. 

 For iodine seven values are computable, thus : 



From ratios 3, 9, and 38 1 = 126.478, ± .0385 



" 3, 24, 38, and Ag 126.807, ± .0192 



" 12 and Ag 126.854, ± .0127 



16 and Ag 126.905, ±.0005 



" 18, Ag, and CI 126.925, ± .0008 



19, Ag, and Br 126.928, ± .0011 



13 and Ag 126.938, ±.0006 



General mean, I = 126.9204, ± .00033 



The first two of these values for iodine are meaningless. The third 

 and fourth involve the determinations made by Stas and Marignac. The 

 final mean, however, agrees with Baxter's determinations to within 1 part 

 in 13,000. 



For potassium there are twelve values, as follows : 



From ratios 9 and I K = 38.6696, ± .0385 



24, Ag, and 1 38.9989, ± .0192 



" 3, 39, and CI 39.0420, ± .0017 



" 1, 3, 31, Ag, and CI 39.0812, ± .00089 



" 22, Ag, and Br 39.0927, ± .00056 



" 23, Ag, and Br 39.0940, ± .00068 



" 21, Ag, and CI 39.1009, ± .00039 



" 20, Ag, and CI 39.1016, ± .00031 



" 3, 40, and CI 39.1097, ± .0085 



" 3 and 38 39.1117, ± .00093 



" 7 and CI 39.1346, ± .00095 



8 and Br 39.3293, ± .0598 



General mean, K = 39.0999, ± .0002 



This value is in good agreement with tlie determinations made by 

 Richards and his collaborators in the Harvard laboratory. 



The eight values for sodium, which come next, are less satisfactory than 

 any of the preceding figures: 



