94 NUTRITIVE PLANTS. 



acid produces more than that of one hundredth, the quantity men- 

 tioned by the chemist of St. Petersburg. 



Since that time M.Vogel has followed up his experiments with 

 more care, in order to acquire an intimate knowledge of the saccha- 

 rine matter, and the mode of its formation. 



To remove every idea of the saccharine matter being the result 

 of simple extraction ; a matter that, having escaped fermentation, 

 was concealed by the starch ; he washed 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. (4lbs. 

 65 oz. avoird.) with 8 kil. of Seine water, acidulated with 40 gr. 

 (0.02 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 is 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 

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

 flannel. 



The liquid having been evaporated nearly to a syrupy consist- 

 ence, it must be left to cool, that more of the sulphat of lime may 

 fall down ; after which the clear liquid is to be decanted off, and 

 the evaporation finished. 



The sugar thus obtained with two hundredths of sulphuric acid 

 in a silver basin was much more saccharine, and less high coloured, 

 than that made in a basin of tinned copper. 



In general the latter cannot be used for the purpose, the tiu being 

 strongly attacked by the long continued boiling. A leaden vessel 

 has been substituted for it with success. 



The 2 kil. boiled with two hundredths of sulphuric acid yiehled, 

 in several comparative experiments, sometimes a little less, some- 

 times a little more, than 2 kil. of syrup at 33 of the areometer 

 (1.295); so from a mean of them we may conclude, without any 

 material error, that starch yields its own weight of syrup. 



As many substances have a decidedly sweet taste, for instance, 

 sugar of milk, the sweet matter iu liquorice, the sweet principle of 



