328 Proceedings of the Royal Irish Academy. 



formed was extracted with ether and washed with a dihite solution of caustic 

 soda. The product was freed from beuzaldehj'de by distillation with steam. 

 The residue was purified from methylated spirit, and was then dissolved in 

 warm alcohol from which by addition of petroleum ether an oily solid 

 eparated. This was recrystallised from warm alcohol. The body finally 

 .obtained consisted of colourless prisms, melting at 176-177" C, soluble in 

 alcohol, chloroform, or acetone, and sparingly soluble in ether or petroleum 

 ether. Its analysis showed that it had a constitution analogous to that of 

 the body obtained in the experiment last described : — 



0'1575 substance gave 0*5143 CO., and 0'1017 H.,0, 

 corresponding to C 89'05, H 7'2. 

 CjgHjgO requires C 88-88, H 6-87. 



D. — Summary. 



1. Butyl-aceto-acetic ester was obtained by the action of n-butyl iodide 

 on the sodium derivative of aceto-acetic ester. 



2. In the presence of alkalies butyl-aceto-acetic ester condensed with 

 piperonal, anisaldehyde, and benzaldehyde to form respectively piperonyl- 

 idene-, auisylideue-, and benzylidene-butyl-acetone together with piperonyl- 

 idene-, auisylideue-, and benzylidene-butyl-acetoacetie acid. 



3. Piperonal and benzaldehyde condensed with butyl-acetone, in tlie 

 presence of alcoholic hydrochloric acid, and at a low temperature, to form 

 crystalline substances apparently derived from three molecules of the 

 aldehyde and one molecule of the ketone in each case. 



