MANUAL FOR SUGAR GROWERS. 119 



leading. The instrument slionld be graduated at a 

 temperature of 81° F. ; sometimes instruments are 

 found graduated at 60° F., the temperature em- 

 ployed when they are to be used in a cold climate ; 

 the readings of such instruments may be corrected 

 by noting the temperature of the liquid tested and 

 adding .0265 for every degree F. above the temper- 

 ature at which the instrument is graduated, or one- 

 tenth for every four degrees difference of tempera- 

 ture. 



Another hydrometer, known as Balling's or Brix's, 

 is commonly employed in the sugar industry. The 

 readings of this scale indicate the percentage of sugar 

 present in solution ; thus 14° Balling indicates a 

 solution containing fourteen per cent, of sugar. 



From what has been said it follows that, when ap- 

 plied to cane-juice, the quantity of sugar can only 

 be estimated approximately by the hydrometer, 

 which is unable to distinguish between cane sugar, 

 glucose, or other dissolved substances. 



In ascertaining the density of cane-juice, it is the 

 common practice to take the juice as it comes from 

 the mill, and to put the hydrometer into this ; this 

 method involves several sources of error. Owing to 

 the presence of air, the fluid appears to be lighter 

 than it really is, and by taking a series of observa- 

 tions on the same sample in rapid succession, a 

 number of increasing densities will be obtained ; at 

 this stage, too, the juice contains in solution a quan- 

 tity of organic matter other than sugar, which is 

 shortly to be removed in the process of clarification. 



