0. G. ^r. MORISON 



1(35 



number of extractions as abscissae. It would seem from these tliat 

 had the extractions been pushed further more phosphoric acid might 

 have been dissolved out. The difficulties of determining such small 

 amounts of phosphoric acid made it impossible to do so. The curves 

 are fairly regular except in the case of B and D, which show some 

 disturbance, considerable in the case of D, at the beginning. 



3 

 Fig. 2. 



This is more clearly seen if, instead of the actual percentages 

 obtained, the logarithms of these numbers are plotted, Fig. 2. The 

 effect which is evident in the case of all four, but most marked in the 

 case of I) and B, is doubtless due to the presence of free lime. If the 

 carbon dioxide were reacting with a single body these logarithmic curves 

 should be straight. As it is it will be noticed that they become so after 

 the first or at the furthest the second extraction, and further that those 



