336 



Mr. E. Schunck. 



[May 7, 



Table VI. — Solubility of Calcium Sulphate in Water in presence of 

 various proportions of Calcium Chloride. Temperature 20°. 



Parts of CaCl 2 in Parts of CaS0 4 in 



100 water. 100 water. 



O'OO -225 



11-50 -078 



14-39 -063 



19-80 -041 



51-00 -000 



67-05 -000 



The addition of common salt, therefore, increases the solubility of 

 calcium sulphate until the proportion of salt to water is 20 or 25 to 

 100. A larger quantity diminishes the solubility. Calcium chloride 

 added to solution of calcium sulphate causes steady decrease of 

 solubility, till when the proportion amounts to about 50 to 100 water 

 the sulphate is practically insoluble. These results are very plainly 

 observable in the accompanying curve (Fig. 3). 



III. " Contributions to the Chemistry of Chlorophyll. Part I." 

 By Edwaed Schunck, F.R.S. Received April 30, 1885. 



(Abstract.) 



The paper treats of the products formed by the action of acids on 

 chlorophyll. All who have worked with chlorophyll are familiar with 

 the peculiar effects produced in solutions of chlorophyll by the action 

 of acids. The colour is changed, and an absorption spectrum makes 

 its appearance which differs from that of chlorophyll. According to 

 some, these changes are due to a simple modification of the chlorophyll, 

 others consider they are caused by the formation of products of 

 decomposition. The latter view seems the more probable. 



On passing a current of hydrochloric acid gas into an alcoholic 

 solution of chlorophyll, a dark green, almost black, precipitate is 

 formed at once. The greenish-yellow liquid contains substances 

 extracted along with chlorophyll by the alcohol, and not connected 

 with the latter. The precipitate consists essentially of two colouring 

 matters, phyllocyanin and phylloxanthin, bodies that had been pre- 

 viously observed and so named by Fremy, who however did not obtain 

 them in a state of purity. They are best separated by Fremy's 

 method, which consists in dissolving the mixture in ether and then 

 adding concentrated hydrochloric acid, when the liquid separates into 

 two layers, a lower blue one containing phyllocyanin, and an upper 

 yellowish- green one containing phylloxanthin. It is immaterial what 



