SACCHARIC ACID. 75 i 



with 8 parts of well pulverised quick-lime. The metacetone is 

 insoluble in water, by means of which it may be freed from 

 acetone. It is a colourless liquid, of an agreeable odour, boiling 

 about 183.2 (84 cent.), and miscible with alcohol and ether. 

 It may be viewed as acetone, minus one atom of water, C 6 H 6 O 2 

 HO=C 6 H 5 O. One atom of anhydrous sugar contains 

 the elements of: 



1 atom of acetone. . . C 3 H 3 O 



1 atom of metacetone . . C 6 H 5 O 



3 atoms of carbonic acid. . C 2 O 6 



1 atom of water. H O 



CU H O, 



12 



Saccharic acid, C 12 H 5 O U + 5HO=C 12 H 10 O 16 (Thaulow). 

 This acid was designated oxalhydric acid by Guerin-Varry ; it is 

 a product of the action of dilute nitric acid on either cane or 

 grape sugar. It is procured by dissolving 1 part of sugar or of 

 gum in 2 parts of nitric acid diluted with 10 of water, and heat- 

 ing so long as chemical action is manifested. The acid liquid is 

 then neutralised with carbonate of lime, and the neutral acetate 

 of lead added to it. The saccharate of lead which falls is decom- 

 posed by sulphuretted hydrogen, and the free acid half neutra- 

 lised by carbonate of potash, and crystallized as the acid sac- 

 charate of potash. The last salt is decolorized by charcoal, 

 converted again into a salt of lead, and the acid liberated by 

 sulphuretted hydrogen. Saccharic acid when concentrated is 

 syrupy, colourless, sharply acid, and deposits colourless crystals, 

 after long repose. It is soluble in alcohol in all proportions, and 

 slightly in ether. It does not precipitate salts of barytes or lime, 

 but produces white flocculent precipitates in barytes-water 

 and lime-water, which are soluble in an excess of acid. 



This acid is remarkable for the variety of compounds it forms 

 with bases. It is supposed to be pentabasic, and to form 5 

 series of salts, according as 1 atom, 2, 3, 4, or the whole 

 5 atoms of water are replaced by metallic oxides ; but it is pos- 

 sibly only tribasic, although capable of forming a subsalt with 

 oxide of lead. Of the following salts, the composition is known 



