191 
I.— LEAD. 
Days Exposed. 
Lead in Solution. 
4 
00301875 
7 
0*0422625 
14 
0-0483000 
32 (expt. 1) 
0-03285625 
32 (expt. 2)..' 
0-0301875 
II.— COFFEE. 
Days Exposed. 
Copper in Solution. 
Copper in Deposit. 
Total Copper 
Dissolved. 
4 
0-20625 
7-00 
7-23625 
7 
0-12250 
11-20 
11-32250 
14 
0-10500 
12-60 
12-70500 
32 
0-10500 
12-95 
13-05500 
Braystonesj near Wbiiteliaven, March 14th, 1877. 
Postcript. March 17th, 1877. 
Since writing my paper, dated March 14th, I have read 
in the Chemical News (of yesterday’s date, March 16th), 
page 110, a paper by Mr. M. M. Pattison Muir, “ On the 
Action of Water and dilute Saline Solutions upon Lead ” 
(read before the Manchester Literary and Philosophical 
Society, Feb. 6th.) I find from this that he has observed, 
while experimenting on the action of solutions of potassium 
carbonate, potassium nitrate, and ammonium nitrate upon 
lead, that the quantity of lead in solution decreases after 
a certain point has been reached. This is similar to the 
results obtained by me in the case of sea>water. As will 
be observed, my experiments also show that this peculiar 
fact applies in the instance of the action of sea- water upon 
copper. In the experiments with sea- water, however, the 
results mentioned could not be due to the same salts us used 
by Mr. Muir, as sea- water does not contain them. 
