Prof. Horsford on the Permeability of Metals to Mercury. 309 
weighed porcelain cup, and was determined at intervals of ten 
days, and finally after a lapse of but four, emptying the enp after 
each weighing. The quantities that flowed through in the pe- 
tiods to ten days were— 
Ist ten days, . aa y oa A169 
ie a : : 5:7906 
3d, « « 86281 
4th,“ # . 41-4976 
Bile) oes 15-4280 
6th,“ « 18-9119 
Teh Mrerey 24-6699 
Sth, « ; ; . 295954 
Oth, Meestios ns, : . 34-6036 
10th, « 5: » 40-0351 
4 days more gav » « 173920 
e : . 
equal for ten days to, 43-4806 
Total, 104 days, 211-9691 
It will be observed that the quantity flowing through in the 
last four days of experiment was not as great a proportional in- 
Crease as that of the preceding ten days. ; 
A second experiment was made with another bar, employing 
the same mercury, now more or less ‘saturated with lead. 
The length of the bar was 0-070 mm. and the diameter 0-006 
_ The first two weighings were at intervals of ten days, the 
remaining weighings once in five days. 
There dropped in the : 
Ist and 2d five days, . » .  48°2735 grammes. 
oa *. Ah ‘ : “ 
66-5655 
5th, igsiiticess . 316409 @ 
6th “ou 29:7585 
7th, ee tan _ 813590 « 
Sth, we ; 30:1640 
9th, i . 96-3460... ..“ 
10th, ‘“c (73 % 39-9694 ¢ ; 
11th, Hoe Me 36-0043 
12th, « « 312365 « 
13th, aia ee 31-5286 .. « 
1th, Cee 319999 « 
Total, 70 days, 4438452 * 
The first suite of experiments led directly to the conclusion, 
that the increased flow of mercury in a given time, was due to 
the increased porosity of the lead—to increased capillary attrac- 
— The second suite of experiments did not sustain this con- 
Clusion. In the first place contrary to expectation a new ba 
transmitted more ihereuty, than the bar conceived to have be- 
Come highly porous by use. And in the second place the quan- 
