Mr. Smee on the Amalgamation of Zinc. 425 



acid and dilute sulphuric acid, yields ten cubic inches of ^as 

 in five minutes. In this case about eight square inches and a 

 half of carbon were exposed, and the communication was ef- 

 fected by means of thick platinum wires. The same quantity 

 of gas was driven off from seven square inches of platinum. 

 One piece of charcoal in a single cell gave one fifth of a 

 cubic inch in twenty minutes. 



Experiments were performed on the properties of selenium, 

 sulphur, phosphorus, bromine, iodine, and chlorine : but as 

 nothing very worthy of notice was discovered, it will be un- 

 necessary to dwell upon these substances. 



The rationale of amalgamating zinc would appear to be ex- 

 actly the converse of platinizing platinum or the other metals, 

 for the one favours the adhesion of the hydrogen and prevents 

 thereby local action, the other favours the escape of the hy- 

 drogen by its non-adhesion, and in that way increases the 

 power. The reasons which I have to offer in support of these 

 opinions are the following : — 



When zinc dissolved in mercury is placed in dilute sul- 

 phuric acid no action takes place, because the gas cannot be 

 readily evolved, but coats the whole surface ; but that there 

 is action really produced, is shown by adding nitrate of silver 

 or sulphate of copper, when the nascent hydrogen is evidenced 

 by the reduction of these metals ; as soon as the whole of the 

 metal is reduced it is again inactive, although the elements 

 of a powerful current are there, namely, zinc, silver, acid ; 

 now touch the mercury by a piece of silver or the negative me- 

 tal, the gas will be immediately evolved from it. This expla- 

 nation appears to me to account for every phaenomenon con- 

 nected with the remarkable properties of amalgamated zinc, 

 which is further confirmed by the attempt to make a galvanic 

 battery with zinc and mercury, the junction being effected 

 exterior to the acid solution, as here great adhesion will be 

 seen to exist between the hydrogen and the mercury. 



In conclusion, I have to regret that the continuity of the 

 paper has been necessarily interrupted, but it is a matter of 

 no great consequence, as it treats of many rather dissimilar 

 properties. 



Bank of England, April 10, 1840. 



Phil. Mag, S. 3. Vol. 1(3. No. 104. May 1840. 2 F 



