280 
PROCEEDINGS 1849 — 1858. 
already described, there was found a miniature mineral lode formed 
of the carbonate of copper, interspersed with red oxide and occasionally 
beautiful particles of native copper. Mr. Hunt concluded by observing 
that he thought there existed a force beyond that of electricity, which 
they did not comprehend ; but that in such general terms as 
molecular and catalytic forces there was expressed a set of phenomena 
which belong to a physical force differing materially from an}^ of those 
with which science has hitlierto made us acquainted. At the same 
meeting, Mr. E. W. Brayley, F.R.S., of London, delivered a lecture 
on the essential conditions of the metamorphosis of rocks. It is only 
printed in brief abstract. 
During the same year, ^Ir. William Baker, of Sheffield, read a 
paper explaining the process for the purification of lead by crystalliza- 
tion, in which he showed that copper may be separated from lead b)'' 
the process introduced by Mr. H. L. Pattinson in 1833, for the pur- 
pose of obtaining silver from lead ore. At a meetiug in Bradford, in 
1858, "a paper on the lead mining districts of Yorkshire, was read by 
Mr. Stephen Eddy, of Carlton Grange, Skipton. In the metalliferous 
portion of the carboniferous rocks, lead occurs in rake veins, pipe or 
tube veins, and flat veins. The rake vein consists of a rent or fissure 
of great length, and often unknown depth. The pipe vein, generally 
occurring in limestone, is an irregular cylindrical tube, which passes 
more or less diagonally through the strata, whilst tlie flat vein is 
seldom met with except in connection with a rake vein, and has 
always a position conformable to the stratum in which it occurs. 
Rake veins are the most common, they vary greatly in width, from a 
foot or two, to as many yards, and then contracting to a mere point. 
They are generally most expanded in limestone or gritstone, and often 
scarcely perceptible in shale. The vertical extent of fault or throw 
most favourable to mining is from 6 to 18 feet, the faults vary greatly 
in direction. The Old Gang vein in Swaledale has been worked for 
many miles in length, and can be traced to a much gTeater distance 
in a nearly straight line. The lead veins in Swaledale, Arkendale, 
and Wen sley dale, are generally more irregular in size, and the beds 
of a more uniform thickness than in the three southern districts, 
Airedale, Wharfedale, and Nidderdale. In the former the lead 
