180 Obituary Notices of Fellows deceased. 



that the acid of Simpson and the acid of Dessaignes were identical 

 compounds. Wichelhaus proved this to be the case. 



The real composition and the structure of tricarballylic acid were, 

 however, inferred from Simpson's experiments. Tricarballylic acid is 

 interesting in consequence of its relation to citric acid, the latter being 

 the oxyacid of the former. A trivalent alcohol like glycerine can form 

 three cyanides : 



C 3 H 5 (OH) 3 ~* C 3 H 5 (OH) 2 Cy .- C 3 H 5 (OH)Cy 2 C 3 H 5 Cy 3 



Each of these may be expected to produce with potassic hydrate 

 solution a corresponding potassium salt. Simpson made the experiment 

 with dichlorhydrin, and obtained potassic oxypyrotartrate (/3 oxy- 

 glutaric acid T) : 



C 3 H 5 (OH)C1 2 -* C 3 H 5 (OH)Cy 2 -* C 3 H 5 (OH) (CO 2 H) 2 



. Oxypyrotartaric 

 Acid 



- Cy 

 The compound CH 3 C - OH, obtained from aldehyde and hydro- 



H 



cyanic acid gave Simpson and Gautier, under similar conditions, potassic 

 lactate, thus confirming the synthesis of lactic acid from aldehyde and 

 prussic acid by Strecker. 



A mixture of alcohol, aldehyde and hydrochloric acid produce on 



standing monochlorether Q 2 jj 5 rn f 0. As aldehyde and acetone are 



considered to possess an analogous constitution, Simpson expected a 

 similar reaction to occur in a mixture of alcohol, acetone and hydric 

 chloride, with the formation of the compound C 5 HnC10. If in this 

 compound the chlorine is replaced by cyanogen, and then the new 

 cyanide boiled with potassic hydrate, the potassium salt of leucic acid 

 might be formed and the synthesis of this acid thus be* effected : 



CsHnOCI, CsHnOCy, C 5 H n O C0 2 H = C 6 H 12 3 . 



A series of elaborate experiments gave Simpson not the expected 

 results. The principal product was a derivative of mesitylic oxide : 



2(C 3 H 6 0) + 2HC1 = C 6 H 12 OC1 2 + H 2 O. 

 and C 6 H 12 OC1 2 , C 6 Hi 2 OCy 2) C 6 H 12 OCy CO 2 K. 



Only one equivalent of cyanogen being converted by boiling potassic 

 hydrate into the group C0 2 H. The hydrogen salt C 6 Hi 2 OCy C0 2 H, 

 called mesitylic acid, was obtained in well-defined crystals, which have 

 not been further examined by Simpson. (" P.," xvi, 364.) 



