224 Professor How on the Ethers and 



which represents the ether of comenamic acid, a substance 

 analogous to the ether of oxamic acid, the oxamethane of 

 Dumas. On the same principle of nomenclature, the new 

 compound may be called comenamethane ; in the crystallized 

 state, it has two equivalents of water, which it readily loses in 

 the water- bath : 



| 19-780 grains, air-dry, lost at 212 c , 

 { 1-790 ... water, 



giving a percentage of 9-04; and 8*95 is the number required 

 by a loss of two atoms of water from the formula ; 



C, H 6 0, 6 U H 4 NO. + 2 aq. 



Comenamethane is perfectly neutral to test-paper. It dis- 

 solves completely, but by no means easily, in boiling water 

 and is deposited on cooling in groups of colourless prismatic 

 crystals ; it is very sparingly soluble in water at the ordinary 

 temperature. Rectified spirit also takes it up in the heat to 

 some extent, but absolute alcohol dissolves it sparingly in its 

 hydrated state, and scarcely at all when dried. All the mi- 

 neral acids dissolve it at once with extreme ease, nitric acid 

 converting it after some time into acid oxalate of ammonia, 

 which crystallizes out in beautiful rhombs. It fuses at a tem- 

 perature above 400° Fahr. into a yellowish liquid, which con- 

 cretes to a crystalline mass, or sometimes remains a pellucid 

 solid when cold. It is unaltered by ammonia in the cold, and 

 undergoes no change if it be heated, deprived of its own water 

 of crystallization, with a solution of the dry gas in absolute 

 alcohol, in a sealed tube, for four hours in the water-bath. I 

 hoped, in this manner, to obtain a neutral amide, but found 

 that the ether is unchanged under these circumstances ; if 

 water be present, the reaction results in the production of 

 comenamate of ammonia, a substance easily identified by its 

 reactions. 



It may be remarked as a characteristic of comenic acid, that 

 all attempts have failed to produce with it neutral salts of the 

 fixed alkalies or ammonia, and also that no neutral ether and 

 corresponding amide can be formed, as is the case, on the con- 

 trary, with many bibasic acids. At least, I have resorted to 



