66 Dr. Debus on Glyoxal. 



a supei-ficial disintegration or decomposition, but I could not by 

 the microscope or by polarized light detect a difference in its 

 structure. I hope, however, to do so by a more prolonged and 

 varied examination. 



It may be well to state that counter experiments were made, 

 such as allowing the plates to remain with the letters between 

 them, but without electrization, in which case no effect was pro- 

 duced ; but it is probable,by analogy with Moser's class of phaeno- 

 mena,that a veiy long period of contact would produce some effect. 



T 



IX. On Glyoxal. By Dr. H. Debus*. 

 IHE great difficulty of preparing glyoxal quite pure led me 

 _ to deduce the formula of this substance from the com- 

 position of its compounds, and the alterations it undergoes in 

 contact with other bodies. But since the second memoir on this 

 subject was written I have succeeded in analysing pure glyoxal, 

 and find that its composition must be expressed by the formula 

 Q2 02 . H^. It is hydruretted oxalyle. 



Since acids contain as many atoms of hydrogen and carbon 

 as their corresponding aldehydes, the formula of glyoxylic acid 

 is probably C^H^ 03. 



The common aldehyde is monobasic, and only one acid corre- 

 sponds to it. 



The bibasic glyoxal forms, on addition of oxygen, two acids, — 

 fflvoxvlic and oxalic acids. 



C^H^O + O = C2H402 



Aldehyde. Acetic acid. 



Glyoxal. Glyoxylic acid. 



C^O^.H^ + 20 = C^O^.O 

 HH.O 



Oxalic acid. 



O = C^H^O^ 



Common alcohol. Glycol. 



C-iHsO^ - 4H = 0^02. H2 



Glyoxal. 



C20^H2 + IPO = C^H^O^ 



Glyoxal. Water. Glycolic acid. 



Therefore glyoxal is the aldehyde of the alcohol glycol, and of 

 glyoxylic and oxalic acids. From the formula of glyoxal, C^ H^ 0^, 

 in my second memoir, one atom of water must be deducted. 

 Queenvvood, December 25. 



* Communicated by the Author. 



