SPECIFIC GRAVITY. 189 
tions of carbon in different samples of sugar analyzed by 
Prout: 
Per cent. of Carbon. 
Pure sugar candy, or best refined sugar..........0.0006 42°85 
MmeGHI MUTA SUCRE CAMMY los 2ceceencnstesrexcnccacesecncus socks 41:90 
East India raw sugar, dry and of low quality......... 40-88 
pupat trom Narbonne HOnGY s...0. 50.0. s0ssss ec sqsscensesns 36°53 
DBupar from starch............-ccescsecsers ok ere ret 36°20 
InN A SOLUTION of sugar most of the tests above given 
cannot readily be applied. Only such means can be em- 
ployed as will not disturb the delicate equilibrium of the 
chemical forces: upon which the existence of the sugar 
depends. ‘The per cent. of sugar in a pure solution may 
be most readily ascertained by taking its specific gravity, 
and this is the use of the hydrometer or saccharometer. 
But this instrument can give correct indications in a pure 
solution only. If other substances than sugar are in the 
solution, they will of course affect its density, and a false 
indication will be the result. 
Moreover, in a pure saccharine solution, composed of cane 
sugar mixed with grape sugar, the hydrometer does not 
enable us to determine their relative proportions. Accord- 
ing to Ure, “ At 1°342 syrup of cane sugar contains 70 per 
cent. of sugar; at the same density syrup of glucose or 
grape sugar contains 754 per cent. of concrete matter, dried 
at 260° F., and therefore freed from the 10 per cent. of 
water which it contains in the granular state.” These sugars 
thus differ from each other in the relative densities of solu- 
tions containing equal weights of each respectively. Hence, 
in even a completely defecated sample of cane juice, the 
indications of the hydrometer are of little value, for they 
give us no means of distinguishing between the different 
kinds of sugar present in the mixed solution. When the 
per cent. of grape sugar in a liquid is already known by 
