316 Prof. Horsford on the Permeability of Metals to Mercury. 
‘VII. Does the mercury volatilize from the saturated tin bar? 
An affirmative reply might perhaps have been anticipated from 
the results with lead. In this however as in other respects the 
tin and lead are greatly unlike. 
ar of tin saturated with mercury was weighed at intervals 
of ten days. Its weights were as follows— 
Ist, j ° 52061 grammes. 
After 10 days, . ‘ 52061 i 
Mc 20:6 ‘ 52061 * 
* ee ; : 52061 8 * 
It crystallizes very soon after becoming saturated, and then as in 
the case of the lead volatilization ceases. 
Experiments with Gold.—The progress of mercury in a bar of 
gold is exceedingly slow. This fact was observed by Daniel. 
Under favorable circumstances, in a strip of rolled American 
coin 0-0006 mm. in thickness, the mercury rose, 0-008 mm. in a 
period of 240 days. The surface of the mercury around the gold 
was coated, with a coherent solid amalgam. 
Mercury coming in contact with gold, as is well known, rapidly 
combines with it. The depth to which mercury penetrates, 
seems to be influenced by considerations, something like those 
which prevail with lead. 
_ Experiments with Silver—The progress of mercury in silver 
1s scarcely more rapid than in gold. It rose in a strip of Ameri- 
can coin 000009 mm. thick, but 0-0085 m. in 240 days. 
The circumstance that both the above metals were rolled, and 
of course compressed—and the fact that both were alloys, doubt- 
less impeded the flow of the mercury: 
ined a semi-liquid drop at the eud of the shorter 
leg, 250 days, that being the period of observation. 
Eirperiments with Cadmium.—A syphon of cadmium was pte- 
red in the manner of the zinc syphon. It dissolved rapidly 19 
the mercury, but there appeared after sometime, an enlargement 
of the body of the bar 0-006 mm. from the end of the shorter leg, 
which resembled that in the bars of lead, except that it did not 
crack open. 
Experiments with Platinum, Palladium, Iron, Copper and 
Brass, gave only negative results. The permeability of several 
of these metals to molten tin, gold and silver and of iron to mol- 
ten copper, is well known. 
