U24 



a c 



c 'fe 



j~=: 



ROCHESTER ACADEMY OF SCIENCE. 



b 



[April iS, 



ll 



4 d' 



FIG. 2 



The regulator is connected by glass 

 and rubber tubing with the separator (fig. 

 2). The latter consists of two distinct 

 parts of glass, the separating tube proper 

 /, a, h and the draw-tube b. The liquid 

 enters at a^ flows at / in the closed space 

 of the inner tube g and mounting upward 

 to / escapes by the tube //. The rubber 

 cork e must close the tube g in such a 

 way as to leave only a small circular pass- 

 age. With a little practice it is easy to 

 place the cork so as to fulfill this con- 

 dition and to regulate the entrance of the 

 liquid in the tube ^ at will. Inside of g 

 is a loose spiral of fine platinum wire of 

 about y^ mm. diameter and with about 40 

 coils of 5.5 mm. diameter, the object 

 of which will be explained later. 



The substance to be separated is 

 introduced through the funnel-shaped 

 opening / and remains wholly in the tube 

 g which should be so arranged with refer- 

 ence to the cork e as not to allow it to 

 escape. If in especially heavy mixtures, 

 grains accumulate at one side so as to 

 partially close the entrance to the tube^'" 

 they can easily be displaced and set in 

 motion by giving a slight tap to the 

 iji apparatus. 



In the connecting tube 

 between regulator and sep- 

 arator are placed two cocks, 

 of which one a (fig. 3) is an 

 ordinary glass cock, while 

 the other is a "precision 

 cock" whose construction is 

 readily seen from figs. 3 and 4 

 and which will be referred 

 to farther on. 



