1870.] Mr. E. Hull on the Temperature of Strata. 



173 



Melbourne: — Flagstaff Observatory. Meteorological Observations, 1S57 

 -53. 2 vols. sm. fol. Daily Meteorological Register, 1S59-1S63. 

 5 vols. fol. Original Observations on Atmospheric Electricity, 1858. 

 sm. fol. Daily Electrical Register, 1 $60-63. 3 vols. 4to* Mag- 

 netical Observations, 1st May to 31st Dec. 1S5S. sm. fol. Re- 

 marks and Disturbance Observations during the year 1S59. Daily 

 Magnetical Register, 1860-62, and Jan. to Feb. 1S<;3. 3 vols, 

 sm. fol. MSS. Presented by the Observer. Dr. Xeuniayer. 



The following communications were read : — 



I. "Observations on the Temperature of the Strata takeu during 

 the sinking of the Rose Bridge Colliery, Wigan, Lancashire, 

 1868-69." By Edward Hull, M.A., F.R.sT, Director of the 

 Geological Survey of Ireland. Received November 27, 1869. 

 In an elaborate paper by Mr. "W. Hopkins, F.R.S., entitled "Experi- 

 mental Researches on the Conductive Powers of various Substances," pub- 

 lished in the Philosophical Transactions for 1S57, an account is given of a 

 series of experiments made under the general supervision of Mr. Hopkins 

 himself and Mr. W. Fairbairn, F.R.S., during the sinking of the Astlev 

 Pit of Dukenfield Colliery in Cheshire*. At the time this paper was 

 written the depth attained was only a little more than 1400 feet ; and the 

 rate of increase between the depths of 700 feet and 1330 feet was found to 

 be 1° F. for about 65 feet. These observations were subsequently continued 

 until the pits had attained their full depth of 717 yards from the surface. 

 The last observation made was in the shale overlying the coal-seam, known 

 as the " Black Mine," which it was the object of the proprietor, Mr. Astlev, 

 to reach, and the temperature was found to be 75° F. Assuming the " stra- 

 tum of constant temperature," or, as it is also called by Humboldt, M the 

 invariable stratum," to be that which was reached at 16 "5 feet with a 

 temperature of 51° F., the total increase of temperature would amount to 

 24° F., giving as the rate of increase 1° F. for every 88*925 feet. This is 

 much below the average rate of increase. 



During a part of the period above referred to (from 1854-56) another 

 coal-pit was being sunk at "Wigan, which reached the depth of 600 yards, 

 down to the celebrated " Cannel Miue." At this pit similar observations on 

 the temperature of the strata were made very carefully by the manager, 

 Mr. Bryham, which were kindly communicated to myself for publication, 

 and will be found in my work on the 1 Coalfields of Great Britain.' The 

 ultimate temperature attained in this pit at the depth from the surface of 

 600 yards was found to be 72° F. ; and assuming the invariable stratum to 

 be the same as that at Dukenfield Colliery, the resulting rate of increase 

 would be 1° F. for every 61*5 feet,' which accords very closely with the 



* The entire series of these interesting observations were kindly supplied to me by Mr. 

 \Y. Fairbairn, and are published in 1 The Coalfields of Great Britain,' 2nd edit. p. 226. 



