ELECTROLYTES. 



219 



0.4 weight-normal solution of lithium chloride, encouraged the hope 

 that it would be found practicable to measure the osmotic pressure of 

 much more concentrated solutions of that salt. But when we proceeded 

 to the investigation of the higher concentrations, it was found that the 

 injury to the membranes by the electrolyte increased rapidly with 

 increasing concentration of solution. The pressure of the 0.5 and 0.6 

 weight-normal solutions were successfully measured, but only by the 

 sacrifice of two of the best cells in our possession. It was not possible 

 to duplicate these determinations with any other cells which were 

 available at that time. The effect of lithium chloride upon the copper 

 ferrocyanide membrane appears to be milder than that of potassium 

 chloride, but not different in kind. 



Table 76. 



Mean osmotic pressure for 100 days, 18.789. 



The conclusions to be drawn from the experiences thus far reported 

 are : (1) that it is practicable to measure the osmotic pressure of lithium 

 chloride in all aqueous solutions not more concentrated than the 0.6 

 weight-normal; (2) that it will probably be found possible to measure 

 the osmotic pressure of potassium chloride in aqueous solutions less 

 concentrated than the 0.5 weight-normal. 



It is hoped that other semi-permeable membranes may be found 

 which are less susceptible to the deleterious influence of electrolytes 

 than are the ferrocyanides of copper and nickel. 



