698 



pionate of soda, but formiate of soda, with evolution of olefiant gas. 

 The reaction, accordingly, might be represented thus : 



' 4 Na 



arid would consist in the replacement of C 4 H 4 by C 2 O 2 . 



On inspection of Dr. Geuther's paper it appeared that the above 

 reaction was not established with sufficient certainty. The presence 

 of C 4 H 4 as a gaseous product was not satisfactorily proved by direct 

 experiment, but inferred from the production of formiate of soda. 



Berthelot has shown that carbonic oxide is capable of uniting 

 with the hydrated alkalies, so as to form alkaline formiates. Also, 

 it is extremely difficult, and perhaps impossible, to obtain sodium- 

 alcohol free from hydrate of soda. It seemed, therefore, not un- 

 reasonable to suspect that Dr. Geuther's formiate came from hydrate 

 of soda accompanying the sodium-alcohol employed in his experi- 

 ments. The investigation about to be described shows that such was 

 really the case. 



Sodium-alcohol, freshly prepared from sodium and anhydrous 

 alcohol, was introduced into small glass bulbs, and hermetically 

 sealed therein. One of the bulbs, containing *406 gramme of 

 crystallized sodium-alcohol, was placed in a flask of 155 cubic 

 centimetres' capacity. The neck of the flask was contracted 

 before the blowpipe. Carbonic oxide, after slow passage through 

 potash solution, and then through sulphuric acid, was next made to 

 fill the flask by displacement. Finally, the contracted neck of the 

 flask was closed by fusion, and thus the bulb containing sodium- 

 alcohol was inclosed in an atmosphere of pure oxide of carbon. By 

 agitation the inclosed bulb was broken, and its contents came freely 

 in contact with the carbonic oxide contained in the flask. Particular 

 attention was paid during this stage of the process, and the fused 

 sodium-alcohol was seen flowing over the inner surface of the flask. 



After a digestion in the water-bath lasting for more than four 

 hours, the flask was opened under mercury, when a slight contrac- 

 tion was observed in the volume of its gaseous contents. This con- 

 traction, amounting to about one-fifth of the entire contents, was due 

 no doubt partly to absorption of carbonic oxide by traces of hydrate 

 of soda, and partly to the difference between the temperature at the 



