272 Chemical Tests and Analyses 



SPECIFIC GRAVITY 



AeromEtric Method by Means oe Beaume Hydrometer 



APPARATUS 



Beaume Hydrometer. — Use a specially constructed Beaume 

 hydrometer with mercury bulb, and a scale of 30 to 37 degrees B., 

 graduated to tenths degrees. Length over all, twelve inches ; length 

 of spindel, six inches ; length of empty bulb, four and one-quarter 

 inches ; width of empty bulb, thirteen-sixteenths of one inch. 



Hydrometer Jar. — Use a glass or tin cylinder with substantial 

 base, minimum length twelve inches, minimum width one and a half 

 inches. 



DETERMINATION 



The Beaume hydrometer is graduated to read correctly at 60 

 degrees F. (15.5 degrees C). At this temperature the sweetened 

 condensed milk is too viscous for rapid and accurate work. Warm 

 the condensed milk to 100 degrees F. or above and correct the 

 Beaume reading by adding to the observed reading 025 points for 

 every degree Fahrenheit above 60. At a temperature of 100 degrees 

 F. or above, the reading can be made in fifteen minutes or less, after 

 the hydrometer is inserted in the milk. 



The specific gravity is determined by the use of the following 

 formula : 



Specific gravity = ^^^3_-g ' 



B = Beaume reading at 60 degrees F. 

 Example: Observed Beaume reading at 120 is 31.6. 



Corrected reading = 31.6 + [(120 — 60) X .025] = 33.1 



144 3 

 Specific gravity = 144 3 _ 33^ = 1-2977 



The following table shows the specific gravity of sweetened 

 condensed milk when the Beaume reading is known. 



