28 



MILK ANALYSIS 



Reduction by Hydrogen. The cuprous oxid is collected on an 

 asbestos filter. This is arranged most conveniently in a special 

 filtering tube, which is shown in figure 6. The wider part 

 is about 8 cm. long and 1.5 cm. in diameter, the narrower por- 

 tion about 5 cm. long and 0.5 cm. in caliber. A perforated 

 platinum disk is sealed in just above the point of narrowing. 

 The asbestos is placed on this disk, washed free from loose fibers, 

 dried well, and the tube weighed. The filtering tube is attached 

 to an exhaustion apparatus by passing narrower portion through 

 the cork, and a small funnel is fitted tightly in the top of the 

 tube. The object of this funnel is to prevent the precipitate 

 collecting on the upper part of the tube. The lower end of the 

 funnel should project several centimeters below the bottom of 

 the cork through which it passes. 



