110 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 54 



When applied to the determination of the atomic weight of potassium, 

 the Richards and Mueller ratios yield almost absolutely identical results, 

 which also coincide with the figures obtained by Richards and Staehler 

 with the chloride. This agreement is strong evidence in favor of the 

 new determinations. 



The ratio between silver and potassium iodide seems to have been 

 measured only by Marignac,' but without remarkable accuracy. The 

 figures are as follows: 



Mean, 153.6994, ± .0178 



Corrected to a vacuum by Marignac, this becomes 153.800. 



THE SODIUM HALIDE-SILVER RATIOS. 



The ratio between silver and sodium chloride has been fixed by several 

 investigators. Pelouze " dissolved a weighed quantity of silver in nitric 

 acid, and then titrated with sodium chloride. Equivalent to 100 parts 

 of silver he found of chloride : 



54.158 



54.125 



54.139 



Mean, 54.141, ± .0063 



By Dumas ' we have seven experiments, with results as follows 



NaCl. Ag. Ratio. 



2.0535 3.788 54.211 



2.169 4.0095 54.097 



4.3554 8.0425 54.155 



6.509 12.0140 54.178 



6.413 11.8375 54.175 



2.1746 4.012 54.202 



5.113 9.434 54.187 



Mean, 54.172, ± .0096 



^ Oeuvres Completes, 1, 86. 



i'Compt. Rend., 20, 1047. 1845. 



8 Ann. Chem. Pharm., 113, 31. 1860. 



