EXCLUSION OF AIR FROM AMALGAMS. 



19 



The amalgams made up by the method described above were separated 

 from the supernatant liquid and bottled up clean and dry in suitable reser- 

 voirs with the help of the device shown in figure 2. G is a hydrogen 

 generator of the Richards type, in which hydrochloric acid containing about 

 8 per cent of the anhydrous gas and the best obtainable grade of granulated 

 zinc were used. A trace of cupric chloride was added to hasten the action. 

 The gas thus obtained was purified by passing it through three Emmerling 

 towers, E lf E 2} and E 3 , each 50 cm. high and 5 cm. in diameter, filled with 

 glass pearls moistened with a very strong solution of pure caustic soda. The 

 gas thus obtained contains no acids that might attack the amalgams, and is 



Fig. 2. Device for Preserving Amalgams. 



fairly dry. The pipette B is fused at A to the delivery tube, and also communi- 

 cates with the vacuum through H and V. The outlet tube of B, terminating 

 in a thick-walled capillary, passes through the rubber stopper K into the 

 flask F, which is provided with two sidenecks, C and D ; C is fused to an 

 open capillary, and D is connected with the aspirator. S t , S 2 , S z , S 4 , S 5 , 

 and S 6 are glass stopcocks well lubricated with paraffin-rubber lubricant. 

 The only rubber in the apparatus proper, the stopper K, was boiled with 

 sodic hydroxide solution and several portions of distilled water ; before using 

 it was covered with soft paraffin. The consistent use of fused joints prevents 

 leakage and the introduction of sulphur compounds from rubber. 



