FORMATION OF THE SOCIETY : UNPUBLISHED RECORDS. 19 
given point determine its state of purity. Instruments for as- 
certaining the quantity of air passing into the workings would be 
desirable. Another point for investigation would be as to whether the 
water found in coal when newly opened out, actually exists in it in 
the state of water or in any other form, which, when exposed to the 
atmospheric air forms water. I have so little to say on this subject, 
which I am afraid you are already thinking is very fanciful, that I 
regret having mentioned it, but one or two circumstances struck me 
as very singular. 1st, the water issuing from coal when first explored 
by driving the water levels is quite pure and soft like rain water. 
2nd, that as the drifts advance, the water still ''follows to the face,'' 
and the coal gradually becomes dry at a short distance from the face. 
3rd, that when the discharge of water is greatest, there we find the 
least quantity of fire damp. 4th, that when coal is thus dried, no 
cavities are found in working it subsequently which contain water. 
This subject is so interesting, I am sure it will repay the Society for 
bestowing their best attention to it. I have really prolonged my 
letter so much that I begin to wish I had met with you in Leeds, 
for I am sure you will lay it aside before you reach the end. 
Believe me, dear Sir, 
Yours faithfully, 
Thos. W. Embleton. 
A large amount of information was furnished to Prof. Johnston 
for his lecture, prior to its publication, by his Yorkshire friends, 
which was duly incorporated. He appears to have attached con- 
siderable importance to it as representing the state of knowledge at 
that time in coal mining, and all the numerous collateral industries 
which influenced or depended upon it. The order to print the lecture 
was placed at the office of the Leeds Intelligencer, and on the 28th 
July, Mr. Embleton was able to forward proofs to Prof Johnston for 
revision by the Coach " Hero," which ran between Leeds and Durham, 
when railways were not, in this part of the country. In acknowledg- 
ing the receipt of the proofs, Prof. Johnston incidentally stated that 
ho had lately obtained at Whitehaven a bottle of Petroleum, which 
exudes in considerable quantities from the roof of one of the seams. 
The examination of the Petroleum proved very interesting. Prof. 
