132 VOLUMETRIC AND INDIRECT ESTIMATION OF FAT. 



The bearings are all plain, which causes a considerable amount 

 of friction ; the centre of gravity of the rotating system is plnced 

 very high, which causes vibration, due to imperfect balancing, 

 to be marked. The air resistance at high speeds is somewhat 

 great. 



These are serious faults, but are capable of improvement. The 

 two-bottle Beimling machine is the only machine on the market, 

 to the author's knowledge, in which the bottles assume a hori- 

 zontal and radial position when rotating ; in the larger sizes the 

 bottles are nearly, but not quite, radial. This position is advan- 

 tageous, as it allows of the most rapid separation of the fat from 

 the acid liquid. 



Fig. 14. Leffmann-Beam Machine. 



Apparatus, The test bottles consist of flat-bottomed flasks 

 with a sloping upper portion terminating in a graduated neck. 

 The bottles (English make) hold 29 c.c. ; the necks are made of 

 glass tube 5-96 mm. in internal diameter, and are so graduated 

 that 80 divisions = 1-475 c.c. These dimensions are according 

 to a specification laid down by the author, and differ slightly from 

 those prescribed by Leffmann and Beam. The pipettes used are 



15 c.c. for milk, 

 9 c.c. for sulphuric acid, 

 3 c.c. for amyl alcohol mixture, 

 4-5 c.c. for cream, and 

 10*5 o.c. for water. 



