on Alcohol at common Temperatures. 45 



is therefore expressed by the following equation : — 

 .2(C^ m Ba2 03, 2S02) + 7W0 + 6Ba HO 



Baryta. 

 = 4Ba20 S02 + 9H H + 20^ YV BaO^. 



Sulphite of Glycolate of 



baryta. barj'ta. 



The conversion of the latter into glycolate of lime was preferred 

 on account of the greater facility with which it crystallizes. 



The caustic alkalies therefore convert the glyoxal into glycol ic 

 acid. But ifj before adding the alkaline substance, a soluble 

 bisulphite has been mixed with glyoxal, a different decomposition 

 takes place. The liquid turns brown, and soon a dark precipi- 

 tate subsides. 



Some glyoxal was heated with potassium. No cyanide of 

 potassium could be detected in the burnt mass ; therefore glyoxal 

 does not contain nitrogen. Since glyoxal unites with bisulphites 

 of soda, ammonia, and baryta, I examined the capabilities of 

 glycolic acid in this respect. Some of the latter substance, of 

 about the consistency of strong syrup, was mixed with bisulphite 

 of soda. No crystals were formed after one week's standing, 

 although in the case of glyoxal this took place within two or 

 three hours after the preparation of the mixture. It has also been 

 shown that the compound of glyoxal and bisulphite of soda turns 

 brown on addition of caustic potash. On adding the latter to 

 the mixture of glycolic acid and bisulphite of soda, no change in 

 colour was produced. 



Crude glyoxal was dissolved in water, a little diluted nitric 

 acid added, and then evaporated on the water-bath till all the 

 nitric acid had been expelled. A residue of a strong acid reac- 

 tion remained, which on being neutralized with chalk gave cry- 

 stals of glyoxylate of lime, (C^ H^ CaO"*). This salt could easily 

 be recognized by the shape of its crystals, and its chai-acteristic 

 behaviour with lime-water. 



C2H403 + NH03 = C^H^O^ -f NH02. 



Glyoxal. Nitric acid. Glyoxylic acid. Nitrous acid. 

 Glyoxal, prepared from its compound with bisulphite of baryta, 

 furnished the same result on being heated with diluted nitric 

 acid. An excess of nitric acid converts the glyoxal into oxalic 

 acid, — 



C2H4 03 4- 2NH03 = C^H^O" + H204-2NH02. 



Glyoxal. Nitric acid. Oxalic acid. 



Glycolic acid dissolved in water and treated with nitric acid in 

 a similar inanuer did not furnish any glyoxylic acid, but was 

 converted partially into oxalic acid. 



