Prof. Horsford on the Permeability of Metals to Mercury. 315 
liquid issued from the larger leg of the syphon. Upon analysis, 
the liquid was found to consist only of tin aud mercury—the lea 
had been left behind. In the bottom of the cup was found a 
crystallized amalgam of tin and lead. 
V. What is the constitution of the solid crystallized amalgam 
—the bar of tin saturated with mercury. 
Several determinations were made of both mercury and tin— 
the former as sulphide, the latter as stannic acid. The mercury 
determinations were uniformly too high, from the unavoidable 
presence of free sulphur. The tin analyses follow— 
Tin. 
100 parts of amalgam gave 82-9 per cent. 
“ec “ oe ts 82:3 ts 
a3 ce “c “ 82-4 “ce 
‘e “cc “ ‘ir 82:1 “ce 
“ “ “ce “ 82-4 te 
c 6“ “ce 6c 82:9 “cc 
ec ‘a3 “ “ §$2:°5 “ 
577-5 
Average, : : 82:5 
‘Average of mercury, 2 175 
These numbers give very accurately the constitution, 
ls, 
The amalgam that flowed through, gave ~ 
Te P ‘ - ; 1:55 
Leaving mercury, — . : ‘ 98:55 
100 00 
The amalgam that flowed through, leaving the lead behind, 
gave— 
he, 173 
Mercury, 98 27 
100-00 
VI. The bar of tin as it becomes saturated with mercury, 
begins, as remarked above, ta crystallize. 
If at an early stage in the crystallization, the bar is bent, the 
outside cracks off, revealing a pith as distinct as if it had been at 
first cast, and then a sheath cast around it. 
If the crystallization be permitted go on, the fissures penetrate 
to the centre of the bar. Daniel observed, that a square bar split 
into triangular prisms—the separating fissures following diagonal 
Planes. If the top and bottom of the bar were right angled termi- 
nal planes, the crystallization freed a pyramid, at either extreme. 
he bar being irregularly cylindrical, the fissures were formed 
as in the case of the prism—along the lines of least resistance. 
