On the Compounds of Sugar with Bases. 451 



salicine, as has been shown by Gerhardt; by fusing salicine with 

 an excess of caustic potassa, hydrogen is evolved ; the mass 

 must not be allowed to become perfectly white, for then some 

 of the salicylic acid is decomposed. Marchand employed two 

 pounds and a half of potassa to half a pound of salicine. If 

 too little potassa is used, resin and salicylous acid are pro- 

 duced. Marchand found the same formula as Piria. If this 

 salicylic acid be mixed with strong nitric acid the action is 

 exceedingly violent, and picrin-nitric acid is produced ; if, how- 

 ever, it be treated with dilute nitric acid the so-called salicylo- 

 nitric acid is formed, which Marchand has shown to be iden- 

 tical with indigo-nitric acid. — {Journ.fur Prakt. Chem. f vol. 

 xxvi. p. 386.) 



On the Compounds of Sugar with Bases. 



Berzelius determined the atomic weight of sugar from the 

 analysis of the lead salt, which he considered to be a compound 

 of one atom of sugar with two atoms of oxide of lead. Peligot 

 analysed this salt, and also the compounds with baryta and 

 chloride of sodium, and from them he deduced C 24 H 36 O 18 

 as the equivalent of anhydrous sugar, which combines with 

 four atoms of base. But the true equivalent is not yet quite 

 settled, for Berzelius threw out doubts as to Peligot's correct- 

 ness ; and the analysis of the baryta salt, upon which the latter 

 chemist places considerable reliance, has been called in ques- 

 tion by Liebig. With a view to clear up these mysteries 

 Soubeiran undertook a series of experiments on tlje subject. 

 As the compounds are very difficult to burn, he employed 

 chromate of lead mixed with bichromate of potassa. Sou- 

 beiran found exactly the same formula for the baryta salt as 

 Peligot; he could not obtain a compound containing less 

 baryta. Brendecke prepared one with only 18*5 per cent, 

 baryta, while the usual one contains 30 per cent. 



Peligot has examined a combination of sugar with lime ; he 

 considers that it is always formed when lime is brought into 

 contact with sugar ; he found 14 per cent, of lime in it. Daniell 

 however stated that he had obtained a compound containing 

 one third of its weight of lime, by boiling fifteen parts of water 

 with six of lime and ten of sugar for half an hour. Soubeiran 

 could never obtain a compound with so much lime ; the salt 

 he found to be most generally formed is one in which the 

 proportion of the ingredients is as 1:4; this is always pro- 

 duced when the lime is in excess, and the mixture is boiled, 

 or else allowed to stand at ordinary temperatures. Brendecke 

 prepares it by adding half a part of water to a mixture of 

 equal parts of lime and sugar; a resinous mass is formed which 



2H2 



