96 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 54 



Mean, 217.6412, ± .0029 

 Mean, rejecting the seventh value, 217.6440, ± .0024 



Secondly, pure iodine was weighed, converted into hydriodic acid by 

 means of sulphurous acid, and then transformed into ammonium iodide 

 with pure ammonia. As nearly as possible the exact equivalent of silver 

 was dissolved in nitric acid, and added to the iodine solution. ' The 

 trifling excess of silver or iodine was finally determined by titration. The 

 following results were thus obtained : 



Ag. 

 5.54444 

 6.27838 

 4.57992 



Mean, 117.6479, ± .0005 



In Baxter's second memoir the ratio just given was redetermined with 

 variations in the process. Iodine was converted into hych-iodic acid, and 

 precipitated by a solution of silver, taking care to avoid an excess of the 

 latter. The final adjustment was eft'ected by titration, as before. In 

 five of the experiments the silver iodide so produced from a known 

 weight of iodine was collected and weighed. In the following table both 

 ratios are expressed in the form Ag : I : : 100 : x; A representing the 

 direct comparisons, and B the silver iodide syntheses. 



' The starred fijrure is erroneously g-iven in the original. The corrected figure was kindly fur- 

 nished me by Professor Baxter. The seventh experiment in the series Baxter rejects. 



