SYNTHETICAL EESEAECHES ON ACIDS OF THE LACTIC SERIES. 321 



Bimethoxalic add is obtained from its barium-salt by adding dilute sulphuric acid to 

 a concentrated solution of the latter, and agitating with ether. On allowing the ether 

 to evaporate spontaneously, prismatic crystals of considerable size make their appear- 

 ance. These yielded on combustion the following results : — 



•1895 grm. gave -3207 grm. carbonic anhydride and '1334 grm. water. 



The formula 



fCMegHo 



(CO Ho 

 agrees well with these numbers, as seen from the following comparison : — 



Found. 



46-15 



7-86 



45-99 



100-00 



Dimethoxalic acid is a white solid readily crystallizing in beautiful prisms resembling 

 oxalic acid. It fuses at 75°- 7 C, volatilizes slowly even at common temperatures, and 

 readily sublimes at 50° C, being deposited on a cool surface in magnificent prisms. It 

 boils at about 212° C, and distils unchanged. Dimethoxalic acid reacts strongly acid, 

 and unites with bases, forming a numerous class of salts, several of which are crystal- 

 line. In addition to the barium-salt above mentioned we have examined the silver-salt, 

 which is best formed by adding argentic oxide to the free acid, heating to boiling, and 

 filtering, when the salt is deposited in starlike masses of nacreous scales as the solution 

 cools. On analysis this salt gave numbers closely corresponding with those calculated 

 from the formula 



fCMoaHo 



(CO Ago ' 



I. -3883 grm. gave -3258 grm. carbonic anhydride and -1207 grm. water. 

 II. -3635 grm. gave -3033 grm. carbonic anhydride, "1097 grm. water, and -1862 grm. 

 silver. 



III. -2536 grm. gave -2144 grm. carbonic anhydride, -0792 grm. water, and -1302 grm. 

 silver *. 



IV. "2617 grm. gave -1111 grm. metallic silver. 

 V. -2467 grm. gave -1266 grm. metallic silver. 



VI. -3400 grm. gave 4747 grm. metallic silver. 



* The acid of the salt used for determinations Nos. III. and IV. was prepared by adding zincmethyl to me- 

 thyUc oxalate, and then heating the mixture to 120° C. for several hours in a digester. 



