Prof. Horsford on the Permeability of Metals to Mercury. 313 
Weight, =. . beth QZTBis ccs difference. 
20 days later, é 39971 i — 00505 
1Osq%) 3 é 39975 3 +0:0004 
19 a rfhi5'g@ ; 3°9978 i +-0:0003 
At first the mercury on the outside and ends, was at the sur- 
face volatilized. The crystalline amalgam prevented thereafter, 
the escape of the mercury. 
XI. What change will the saturated bar experience, long in 
contact with the mercury ? ; 
_ A straight bar 0-040 mm. long, placed erect in mercury was 
soon saturated throughout. No sensible change in its texture took 
Place till at the end of one hundred and ninety-four days, the 
portion just below the summit began to enlarge, and crack open, 
displaying at the end of a few days crystallized angles andfsur- 
ace in the interior. The crystallization continued for ninety 
days when the observations were terminated. 
All the vertical bars that from the commencement of ex- 
periment had remained standing in the mercury, nearly equal 
os cracked open, more or less throughout their entire 
ength, 
_ The velocity of transmission was greatly diminished. In 
sixty days there fell only 11-4604 grammes. The texture of 
XIL Does the bar expand at once upon becoming saturated 
with mercury ? 
A piece of finch lead tube was split open, flattened and 
scraped bright, and its length having been accurately ascer- 
tained —-+198 mm, mercury was spread over its entire sur- 
ace, care being taken to avoid the points where admeasurement 
ad been made, and where expansion if it occurred was to be 
observed, 
When the mercury had penetrated to the lower surface of the 
bar admeasurement was again made. The bar had not percepti- 
bly increased in length, nor did it, in the first ten days after the 
Saturation with mereury. 
E'rperiments with Tin.—The fact that tin is permeable to 
mercury was noticed by Daniel. The following inquiries were 
Submitted to experiment. fhe sn 
Szconp Series, Vol, XII, No. $9,—May, 1852. 40 
