OF THE VARIOUS LEAD-SPARS. 
511 
VI. Many years ago, Mr John Taylor, an intelligent 
dverseer at Wanlockhead (about a mile from this), obser- 
ving a drop of water, which was forming an. incrustation 
on the sides of the vein, placed a phial under the drop, to 
ascertain if any crystals would be formed, l3y what dropt 
into the phial. The experiment succeeded so far, that he 
had an incrustation of minute crystals formed on the bot- 
tom and lower part of the inside of the phial, which he 
considered as carbonate of lead. I have seen a piece of 
this phial (for it was broken) ; about two inches of the 
iinder part remain, and is covered with a coating of minute 
splendent crystals. I must, however, remark, that no parti- 
cular analysis of these has been made, so far, at least, as is 
Consistent with my present knowledge. The crystals are 
too minute to allow us to ascertain, even with a magnifier, 
their exact form ; but from their very splendent lustre, and 
appearance in general, I have not the smallest doubt of 
their being the carbonate» 
VII. I would refer those who may still feel sceptical, 
candidly to examine the appearances presented by the 
mines in this neighbourhood, when I think there is no 
doubt that they will be fully convinced of the facts I state 
being sufficient to warrant the conclusions I have drawn. 
I propose to send a few specimens to Professor Jameson, 
which, being deposited in the Museum, may afford those 
who cannot visit the Mines an opportunity of forming a 
more correct opinion on this point, than can be done with- 
out an examination of the whole in siiu. 
It is no difficult matter to imagine how this change may 
be brought about. We know how readily sulphur combines 
with oxygen, to form sulphuric acid, as is evinced in the for<> 
mation of sulphate of iron from iron-pyrites. The lead being 
oxidised by the oxygen, arising from the decomposition of 
L 1 ^ 
