92 iiEPORT — 1881. 



350 yards, in the floor of the Royley Mine. It is in newly opened gronnd, 

 free from cracks or other visible irregularities, at the far end of the newly 

 opened North Level. The depth of the hole, which was in hard warren 

 earth, and the other conditions of observation, were the same as before, 

 and the temperature observed was 62^° Fahr. 



Taking the surface-temperature as 49°, this gives an increase of 13g-° 

 in 1,050 feet, or of 1° for 79 feet. 



AH these stations, as well as Dukinfield, where Mr. Garside last year 

 obtained results in good agreement with those now presented, are within 

 a few miles of each other and close to the river Tame, which is here the 

 boundary between Lancashire and Cheshire. Mr. Garside calls attention 

 to the great quantity of water which is found in some parts of the rock 

 overlying the coal-measures in this district, a source Avhich is largely 

 di'awn upon for water-supply, and suggests, with much show of reason, 

 that its presence may account for the slowness of the rate of increase 

 shown by all these observations. 



Mr. James M'Murtrie, general manager of the Radstock Collieries, near 

 Bath, has taken observations in three different pits belonging to these 

 collieries. The instrument used in each case was one of the Committee's 

 slow-acting thermometers, placed in a hole drilled 2 feet deep, which was 

 jilugged with about 4 inches of clay. A moderate current of air was 

 passing. The level, in each case, was dry and free from cracks, and the 

 face at the place where the hole was drilled had only been exposed a day 

 or two. The rocks overhead consist of lias above, then new red sand- 

 stone, and under this the shales and sandstones of the coal-measures. The 

 mines, speaking generally, are comparatively dry, and the strata were 

 perfectly dry where the temperatures were taken. There are no great hills 

 near, the Mendips being about six miles distant, and the surface rises 

 about one in fifty towards them, leaving out of account local undulations. 

 The strata in all three cases were nearly level. 



In Wells May Pit, the thermometer was left two days in a hole drilled 

 in the sandstone rock at the depth of 560 feet, and read 61'7°. 



In Ludlow's Pit, it was left two days in a hole drilled in the Ball Vein 

 coal, at the depth of 1,000 feet, and read 63°. 



In the same pit it was left five days in a hole drilled in the Middle 

 Vein coal, at the depth of 810 feet, and read 63°. 



All these observations were taken in June and July of the present 

 year. Arranging them in order of depth, and assuming the surface- 

 temperature to be 50°, the result stands thus : — 



They exhibit a large amount of irregularity, which is not easily 

 accounted for. The mean result may be taken as 1° in 62 feet. Mr. 

 Wethered's observations in the Kingswood Collieries, near Bristol (see 

 ' Report' for 1879), gave about 1° in 68 feet. 



