SUGAR OF jtarch: 275 



His discovery, which ■ opens a new career to vegetable His discovery 

 analysis, and may lead to interesting results, has induced Mr. P"''^"^^'^ ^^ 

 Vogel to pursue these new facts. His first experiments, some 

 particulars of which he has given in the Journal de Physique, 

 difi^r scarcely in any thing from those of Mr. KirchofF, except 

 in his observing, that part of the saccharine matter is formed 

 in the course of two hours boiling, and that the proportion of 

 two hundredths of sulphuric acid produces more than that of 

 one hundredth, the quantity mentioned by the chemist of 

 Petersburgh. 



Since that time Mr. Vogel has followed up his experiments 

 with more care, in order to acquire an intimate knowledge of 

 the saccharine matter, and the mode of its formation. 



To remove every idea of the saccharine matter being the Not ready 

 result of simple extraction; a matter that, having escaped ^";"'J'^ "^ ^^* 

 fermentation, was concealed by the starch ; he wa.shed the 

 starch with a stream of cold water, before he made use of it. 



When well dried and reduced to powder, he mixed 2 kil. Method of 

 [4lbs. 6| oz. avoird.J with 8 kil. of Seine water, acldolated P'^o'^"<^'"S^t- 

 with 40 gr. [002 of the weight of the starch] of sulphuric 

 acid at 56° [1-631]. 



He then boiled the mixture in a silver basin for thirty-six 

 hours. There is no danger of its burning, except during the* 

 first hour, when it must be kept constantly stirring with a 

 broad wooden spatula. After that time the mixture grows 

 much more fluid, and requires only to be stirred occasionally. 



It ii essential to keep up the quantity of water, by adding 

 fresh as it evaporates. 



After this boiling, it is to be clarified when cold by means of Clarification, 

 charcoal and chalk, and the whole is to be filtered through 

 flannel. 



The liquid having been evaporated nearly to a sirupy con- Evaporation, 

 sistence, it must be left to cool, that more of the sulphate of 

 lime may fall down ; after which the clear liquid is to be de- 

 canted oft, and the evaporation finished. 



The sugar thus obtained with two hundredths of sulphuric ^ !f ^^^jiYt^^ 

 acid in a silver basin was much more saccharine, afid less tinned coj^pcr. 

 high coloured, than that made In a basin of tinned copper, 

 starch soluble in cold water by a slight torrefaction, and thus assimi- dcrcd soluble 

 lating it to mucilages. See Bidldin de Pharm., torn, in, p, 39.5. ^^^ <^<^'^ ""^^^ ' 



T2 The 



