DETERMINATION OF FATS. 



39 



The optical methods have, moreover, the disadvantage 

 that they are dependent upon the individual perception 

 of each observer. Naturally each eye is not equally sen- 

 sitive in detecting differences of luminosity. Outside 

 conditions under which the test is carried on, also exert 

 an influence on the result. Even for one and the same 

 eye the sensitiveness of the test is 

 not the same in bright sunlight as 

 in cloudy iveather, nor in artificial 

 light, as in daylight, etc. .\lthough 

 these methods are not practicable 

 for very accurate work, they are 

 useful to confirm the doubtful re- 

 sults obtained by more exact deter- 

 minations. They are valuable to 

 the physician, the pharmacist, and 

 especially to the market inspectors, 

 to detect occasional adulteration. 

 The processes have the further ad- 

 vantage that the observer need not 

 be especially skilled. For a close 

 decision of the quality of a sample, 

 however, they are not suited, for 

 the reason just stated. 



The cremometer of Chevalier 

 (Fig. 4) consists of a glass cylinder 

 20 cm. high and 4 cm. in diameter, 

 with a capacity of 160 c. c. 

 It is provided with a hundred-point scale, the zero 

 mark of which is placed 5 cm. below the top rim. The 

 graduations usually are made only from zero degfrees to 

 50 degrees. For the test, the apparatus is filled to the 

 zero mark with milk and allowed to stand for four hours 

 in a room where the temperature is moderate and uni- 



FiG. 4. 



The Chevalier 



Cremometer. 



