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water, and 1 part of sulphuric acid by weight. 
This mixture is to be kept boiling for 40 hours ; 
the loss of water by evaporation being supplied by 
new quantities. The acid is to be neutralized by 
lime ; and the sugar crystallized by cooling. This 
experiment has been tried with success by many 
persons. Sir C. Tuthill, from a pound and a half of 
potatoe starch, procured a pound and a quarter of 
crystalline, brown sugar ; which he conceives 
possessed properties intermediate between cane- 
sugar, and grape-sugar. 
It is probable, from the experiments of M. 
Theodore de Saussure, that the conversion of starch 
into sugar, in this experiment, is effected merely 
by its combination with water; for his experiments 
prove that the acid is not decomposed, and that no 
elastic matter is set free, and that the sugar weighs 
more than the starch from which it is formed : 
probably the colour of the sugar is owing to the 
disengagement, or new combination of a little car- 
bon, the slight excess of which, as has been just 
stated, constitutes the only difference (independent 
of the different quantities of water they may contain) 
perceptible by analysis between sugar and starch. 
M. Bouillon la Grange, by slightly roasting 
starch, has rendered it soluble in cold water ; and 
the solution evaporated afforded a substance, having 
the characters of mucilage. And by experi- 
ments similar to those of M. Kirchhoff, M. Bra- 
connot has lately shown that saccharine and mu- 
cilaginous substances may be procured from vari- 
ous forms of woody fibre ; and I have seen speci- 
mens of soft sugar made from linen rags. 
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