S64 Braconnot on the Formation of Sugar from Linen^ 
stratum of black powder which covers it ; and which, when re- 
moved by washing, is converted into a true gum, resembling in 
many respects gum arabic, and likely to be of some use in the 
arts. This gum is separated from the sulphuric acid in excess 
by means of carbonate of lime, and it remains in the liquor. 
By afterwards treating this gum with sulphuric acid diluted 
with water, at 30° or 40° and in ebullition, it is converted into 
true sugar of grapes ^ the quantity of which is greater than 
that of the sawings of wood or the linen employed. In 
addition to this sugar, which forms almost the whole of the 
mass, M. Braconnot obtained another substance, which he call- 
ed the vegeto-sulphuric acid. It is composed of sulphur, car- 
bon, hydrogen, and oxygen ; or of a vegetable matter, and the 
elements of sulphuric acid. It is separated from the mass by 
rectified alcohol, which dissolves it, and it is freed, from the 
small quantity of saccharine matter which it may contain, by agi- 
tating it, after it has been evaporated into a syrup with ether. 
This acid, when pure, is deliquescent, uncrystallisable, and ex- 
tremely acid. It is decomposed and becomes black, when put 
into a capsule plunged in a sand-bath, even at a temperature be- 
low boiling-water. It produces no change in metallic solutions ; 
does not precipitate nitrate of barytes, nor nitrate of lead ; effer- 
vesces strongly with carbonates ; and it is capable of dissolving 
all the metallic oxides, with which it forms deliquescent salts, 
insoluble with rectified alcohol. When subjected to heat, these 
saline and neutral combinations are decomposed, and emit sul- 
phurous acid, and leave sulphates and charcoal. .This new acid 
dissolves iron and zinc, liberating abundance of oxygen gas. It 
even dissolves sulphate of lead to a certain degree ; and it forms, 
with oxide of dead and barytes, very soluble salts, which have a 
gummy appearance. 
M. Thenard, from whose report the preceding facts are taken, 
announces, that M. Pouillet has been occupied for six months 
in experiments analogous to those of M. Braconnot ; and that 
he has obtained sugar by treating Paper with diluted sulphuric 
acid. 
