SUGAR. 91 



Proust pointed out the difference between it and common sugar. 

 The juice of grapes, according to him, yielded from 30 to 40 per 

 cent, of this sugar. 



It was Marggraf who discovered sugar in the root of the beta vul- 

 garis ; but it is to Achard, as we bave already observed, that we 

 are indebted for the first attempts to extract it from that plant in 

 a large way. The experiments of this philosopher, of Lampadius, 

 of the committee appointed by the National Institute, and of Goet- 

 tling, have thrown more light on this interesting subject. The 

 plan of Lampadius differs but little from the rest. He advises 

 to boil the beet-roots (deprived of the heart) till they become 

 so soft as to be easily pierced by a straw. They are then cut into 

 slices, and the juice forced out by pressure. What remains is left 

 for twelve hours in water, and the whole subjected to the press a 

 second time. The liquids thus obtained are filtered through flannel, 

 boiled down to two-thirds, filtered a second time, reduced by boil- 

 ing to one-third of the original liquid, fiitered a third time, and 

 then evaporated to the consistence of syrup. The crystalline crust 

 which forms on the surface is to be broken from time to time, and 

 the spontaneous evaporation continued till the surface becomes 

 covered with a tough coat instead of crystals. The whole is then 

 to be thrown into woollen bags, and the mucilaginous liquid sepa- 

 rated from the crystals by pressure. 



The sugar obtained by these processes has much the appearance 

 of raw sugar; but it maybe refined by the common processes, and 

 brought into the state of common sugar. From the experiments 

 of Goettling, it appears that beet-sugar is distinguished by a certain 

 degree of a nauseous bitter taste ; owing, it is supposed, to the 

 presence of a bitter extractive matter, which Lampadius has shown 

 to be one of the constituents of the beet. 



The plants containing sugar are very numerous. The following 

 are the chief of those from which it has been actually extracted 

 by chemists. 



The sap of the acer saccharinum, 



- betula alba, 



- ase>*'pias syriaca, 



- heraciiu'u -phondilium, 



- cocos nucifera, 

 juglans alba, 



