ANALYTIC PROCESSES 21 



kept. It should be clear and not very dark in 

 color. It is best kept in a bottle provided with a 

 pipet which can be filled to the mark by dipping. 

 Rigid accuracy in the measurement is not needed. 



[The Leffmann-Beam method is often erro- 

 neously called the "Beimling" method, but 

 Beimling was merely the deviser of a cheap 

 centrifuge. To protect the interest of a manu- 

 facturer who had invested in the Beimling 

 machine under the impression that it was a 

 practicable method for fat estimation, it became 

 necessary for Leffmann and Beam to take out a 

 patent (now expired) and assign the same to this 

 investor.] 



Calculation Methods. — Several investigators 

 have proposed formulae by which when any two 

 of the data, sp. gr., fat, and total solids, are 

 known, the third can be calculated. These differ 

 according to the method of analysis employed. 

 That of Hehner and Richmond, as corrected 

 by Richmond, was deduced from results by the 

 Adams method of fat extraction. It is: 



T = 0.25 G -\- J.2 F + 0.14; 



in which T is the total solids, G the last two figures 

 of the sp. gr. (water being 1000), and F the fat. 

 Patrick has proved that with American milks the 

 constant should be dropped, the formula reading : 



T = 0.25 G -\- 1.2 F 



