CHINESE AND AFRICAN SUGAR CANE. 
369 
sulphurous acid. Its efficacy as an obstacle to fermentation 
was so well proved, its price so low, its production so easy, 
and the substances so universal—merely burning sulphur in the 
atmosphere, that it seemed to answer all the purposes. 
At the same time that M. Melsens was experimenting in Pa¬ 
ris, 1847, Dr. Scoffern was also engaged in experiments upon 
brown sugars, in England, and studying the action of lime up¬ 
on them, he sought for a remedy to deprive the syrup of any ex¬ 
cess which might have been used in the tempering. Under date 
of May, 1847, he says the best plan consists in using sulphur¬ 
ous acid. In July, 1847, he says, he was fortunate enough to 
find an agent to precipitate the fermenting ingredients from the 
juice, which might be used without chemical superintendence, 
everywhere. That agent was sulphurous acid. In another 
place he remarks that there are certain acids from which, under 
no circumstances, was he able to recognize anything injurious 
to the constitution of the sugar. Of these he cited carbonic 
and sulphurous acids. The latter had long been known as an 
anti-ferment. Taking advantage of these properties, he was 
enabled to obtain a specimen of cane juice from the island of 
Barbadoes, in such a state of preservation, that he extracted 
from it upwards of 20 per cent, of sugar. Experiments by 
Melsens, however, proved that while it had the desired effect at 
first, yet being long in contact with air and water saturated with 
sugar, it was converted into sulphuric acid, forming grape su¬ 
gar, and so destroyed the crystals of cane sugar. This effect 
was increased by the heat necessary to the evaporation of the 
juice. 
To prevent this action of the acid, a powerful base, as pot¬ 
ash, soda, or lime was called into requisition, and it was found 
that this base would unite with the sulphuric acid as soon as 
found, and thus the sugar remained intact. Of the salts used, 
the acid sulphite of lime, (bisulphite) presented the most inter¬ 
esting properties. The sulphurous acid in excess prevented all 
fermentation. The base of the salt, lime, neutralized the sul¬ 
phuric acid as fast as it was formed, leaving only a neutral sul- 
