442 
Proceedings of the .Royal Society of Edinburgh. [Sess. 
adding hydrochloric acid to a weighed quantity of solution and collecting 
the dried carbon dioxide in two weighed soda-lime tubes. From the 
amount of carbon dioxide obtained the percentage of potassium carbonate 
could be found, and hence the amount of potassium due to the carbonate 
could be calculated. This being subtracted from the total potassium gave 
the amount due to the potassium ethyl salt, and from this amount the 
Fig. 1. 
percentage of the ester salt could be ascertained. This method, however, 
failed to give concordant results. Finally the following methods were 
adopted. To determine the percentage of potassium ethyl salt, a weighed 
quantity of the solution was acidified with dilute sulphuric acid, when 
hydrogen ethyl di-propyl-malonate was precipitated. The ester acid was 
extracted with ether and washed to get rid of sulphuric acid. The ether 
was then evaporated off, and after addition of a little water the residue was 
titrated with a standard solution of baryta. To determine the percentage 
