DETECTION OF THE ADULTERATION OP CANE SUGAR, 43 
ART. XL— METHOD OF DETECTING THE ADULTERATION 
OF CANE-SUGAR WITH STARCH-SUGAR, AND THE 
SYRUP OF THE FORMER WITH THAT OF THE LATTER. 
By Dr. G. Reich. 
When a boiling saturated solution of bichroniate of pot- 
ash is added to a thick syrup of cane-sugar and the mixture 
heated to boiling, the chromic acid is reduced with a 
violent reaction, which continues even after removing the 
vessel from the fire, and the liquid is coloured green by the 
oxide of chromium in solution. When starch-sugar syrup 
is treated in the same manner, a very different behaviour is 
observed, and which may be employed to distinguish these 
two kinds of sugar ; the starch-molasses has not the least 
action on the bichromate of potash; and when mixed with 
cane-sugar molasses to the amount of ^-i, prevents the re- 
action of the latter ; the mixture merely froths somewhat 
more when heated, but does not change its colour. When 
the amount of starch-sugar molasses is smaller, a slight 
alteration of colour is perceptible ; but it is never so decided 
as with cane-sugar syrup alone. While these syrups may 
be thus distinguished, the sugars themselves cannot be 
determined in this manner, because the bichromate of 
])otash is wholly without action upon the concentrated solu- 
tions of both, but they may be distinguished by nitrate of 
cobalt. When some potash is added to a concentrated 
solution of pure cane-sugar, and the mixture heated to 
boiling, a violet-blue precipitate falls, even when the solu- 
tion is diluted, on the addition of a few drops of nitrate of 
cobalt. The dilute solution of the starch-sugar, treated in 
the same manner, is not precipitated ; and the concentrated 
