Smeeth— Apparatus for Separating Constituents of Rocks. 59' 



Fig. 1, pour in the heavy liquid, and then the powdered rock; now 

 close the opening at the top, and shake up the contents thoroughly ; 

 then allow settlement to take place, and the heaviest particles will 

 subside to the bottom of the bottle, b. When this is accomplished, 

 pass the stopper, s, through the top opening, and, after giving it a 

 few turns in the liquid, to cleanse it, press it into the neck, n, and 

 disconnect the parts of the apparatus, as shown [in Fig. 3. For 

 rapidity, it is convenient to have a second bottle similar to b, into 







which v may now be fitted. The stopper, s, should then be removed, 

 and sufficient water to bring down the next mineral shaken up 

 with the contents. While this is proceeding the specific gravity of 

 the first separation (or more generally of any one but the first) may 

 be very approximately estimated by immersing the plummet of a 

 Westphal's balance in the liquid in b ; because for any separation 

 the specific gravity of the mineral in b will be just between that of 

 the liquid in b and that of the liquid just before the mineral sank. 

 The bottle may now be relieved of its contents, and prepared to 

 receive another separation. 



A rough and ready form of the apparatus may be set up in any 



