310 Proceedings of the Royal Society of Edinburgh. [Sess. 
This table shows that the total uncombined KI molecules added to the 
total combined iodine molecules equals the total number of KI molecules 
present in dilute solutions, while in the stronger solutions up to normal KI 
the iodine is in slight excess, indicating the presence in small quantities of 
higher poly iodides. For the dilute solutions, the results justify the 
method, as the total amount of the uncombined KI agrees very closely with 
the results obtained by Jakowkin and Noyes. As the potassium iodide 
solutions grow stronger and the solubility of the iodine increases, the 
Graph 2. 
amount of uncombined potassium iodide diminishes. The results are more 
clearly shown in graph 2. The total numbers of potassium iodide molecules 
present are taken as ordinates — for curve (a) the total number of combined 
iodine molecules, and for curve (b) the total number of free potassium 
iodide molecules, are taken respectively as abscissae. The straight line (c) 
shows the relation which exists between combined iodine and uncombined 
KI in dilute solutions. 
These results show clearly that up to normal KI there is very little 
polyiodide present higher than KI 3 , if we assume the method to be reliable 
for solutions up to this strength. 
While the application of the Nernst equation is more and more likely 
