1865.] On the Acids of the Lactic Series. 79 



phate of copper is added to a hot solution of tricarballylate of soda. It is 

 insoluble iu water, but soluble in dilute acids. 



Tricarballylate of Lead, C ' 2 *J ^'" J O 6 . 



This salt precipitates when an excess of acetate of lead is added to a solu- 

 tion of tricarballylate of soda. It is a white powder insoluble in water, but 

 soluble in dilute nitric acid. 



The composition of the foregoing salts and ethers fully confirms the view 

 I took of the basicity of this acid in my preliminary paper. It is, I 

 believe, at present the sole representative of its class. It will not, however, 

 I believe, long remain so, as the process by which it has been obtained will, 

 I have no doubt, be found to be of general application. 



This acid bears the same relation to citric acid that succinic bears to 

 malic acid : 



C 12 H 8 O 12 , tricarballylic acid. C b H 6 O 8 , succinic acid. 

 C 12 H 8 O u , citric acid. C 8 H 6 O 10 , malic acid. 



That this relationship exists not only on paper, but also in the nature of the 

 bodies themselves, is, I think, highly probable. In order to arrive at cer- 

 tainty on this point, I have endeavoured, by the addition of two equivalents 

 of oxygen, to transform tricarballylic into citric acid. My researches in 

 this direction have not hitherto been attended with success. 



II. "Notes of Researches on the Acids of the Lactic Series. No. III. 

 Action of Zincethyl upon Ethylic Leucate." By E. FRANKLAND, 

 F.R.S., and B. F. DUPPA, Esq. Received February 1, 1865. 



In describing the production of ethylic leucate or diethoxalate *, formed 

 when zincethyl acts upon ethylic oxalate, we assumed the intermediate 

 formation of zincoleucic ether, and explained the reaction by the following 

 equation, in which zinc is regarded as a monatomic metal ; 



f(C 2 H 6 ) 2 



OC 2 H , C 2 H 5 _ I OZn' Zn' 



- 



OC;H S 



Ethylic oxalate. Ziucethyl. Zincoleucic ether. Zincethylate. 

 In contact with water we conceived zincoleucic ether to be decomposed 

 with the formation of ethylic leucate and zinc hydrate, 

 f(C 2 H 5 ) 2 f(C 2 H 5 ) 2 



p J OZn' , H r J OH Zn'l n 



CU +H 2 = C 2 j Q + H JO. 



[OC 2 H 5 ( OC 2 H 5 



Zincoleucic ether. Ethylic leucate. 



Since these reactions were thus expressed, zinc has come to be generally 

 * Proceedings of the Royal Society, vol. xii. p. 396. 



