OP ARTS AND SCIENCES. 6 



The substance after thorough washing with water was in each case 

 dried on a steam-radiator at a temperature of about 60°. 



I. 0.2552 g. of substance gave 0.6460 g. of COg. 

 0.1476 g. of H.p. Ash = 0.004. 

 11. 0.2449 g. of substance gave 0.6183 g. of CO^. 



0.1368 g. of U.p. Ash = 0.0061. 

 III. 0.2357 g. of substance gave 0.6001 g. of COj. 

 0.1365 g. of up. Ash = 0.002. 



Properties. It resembles the dihydride closely, like it forming a 

 dirty white powder with no definite melting-point, since it melts 

 gradually in the neighborhood of 120°. The best solvents for it 

 are alcohol and glacial acetic acid, but it is deposited on evaporation 

 of the solvent as a varnish. It is essentially insoluble in ether, ligro- 

 ine, and benzol, slightly soluble iu chloroform. A solution of potassic 

 hydrate dissolves it with a yellow color, while potassic carbonate 

 forms a dark-brown solution if boiled with it, but as this solution 

 cools, brownish flocks are deposited, which we supposed to be a potas- 

 sium salt, until two analyses of the substance showed that it did not 

 contain more than 2.5 per cent of potassium, whereas the salt with 

 the least possible amount of the metal contains 7.5 per cent. It is 

 evident, therefore, that the potassium was an impurity, which could 

 well be, since we were able to find no satisfactory method of purifi- 

 cation. An attempt to make a potassium salt with alcoholic potassic 

 hydrate gave a black liquid, insoluble in a mixture of alcohol and 

 ether, and of the most unpromising appearance. 



The fact that the substance forms no salt with potassic carbonate 

 indicates that the two molecules of the dihydride are connected by the 

 removal of water from their carboxyl groups ; but we did not consider 

 the nature of the substance satisfactorily explained until we succeeded 

 in making it from the dihydride, Cj^HjgO^, by the action of an acetic- 

 acid solution of zincic acetate. After warming the two substances 



* If the ash is not subtracted the percentages are, — 



I. II. III. 



69 04 68.85 69.44 



6.43 6.20 6.43 



