ON UNDERGROUND TEMPERATURE. 53 
Professor Harold Dixon in October 1902 with a slow-acting thermo- 
meter made by Negretti & Zambra and tested at Kew inserted in a 
hole 4 feet deep in the floor at the lowest point reached. 
The reading obtained was 100°-6, which confirms the deduction of 
1° in 66 feet. 
In the North Staffordshire coalfieddd Mr. W. N. Atkinson, H.M. 
Inspector of Mines, found the following temperatures at the greatest 
depths reached :— 
Sueyd Colliery, Burslem . : . 87°5 at 2,625 feet. 
Glebe Colliery . ; : . We COne ta a neeO as 
Great Fenton Colliery F 3 , Sb Or? yy, © 2400), ©; 
Assuming 48° as the surface temperature, the mean rates of increase 
downwards are :—- 
Sneyd , é : ‘ : : . 1° in 66°5 feet. 
Glebe 2 : : : : ; fe Odie LOOT Let yyg 
Great Fenton . a 2 : ‘ gee eS GEO)» ce 
The method of observation was to drill a hole, insert a bottle of water, 
and, after leaving it in the hole, plugged with clay, for twenty-four hours 
or more, take it out, and put a thermometer into the water in the bottle. 
In the Sneyd Colliery observations were thus taken at thirteen depths 
during the sinking of a shaft, beginning with 1,104 feet and ending with 
2,625 feet, and the increase shown was fairly regular. The Glebe and 
Great Fenton observations were also in sinking shafts. 
At Hamstead Colliery in South Staffordshire Mr. F. G. Meachem 
made observations extending over several years. He found the mean 
annual surface temperature to be about 49°, and the temperature of the 
undisturbed strata at the bottom, 1,950 feet deep, 66°. This last was 
ascertained by inserting a maximum and minimum thermometer, pro- 
tected by a metal case, into a bore-hole driven ten feet into freshly cut 
coal. The hole was closed with clay and left for various periods from 
one to fourteen days. 
Repeated observations gave the same result. The rate of interest 
hence deduced is 1° in 115 feet. A surface temperature of 48° would 
give 1° in 108 feet. Mr. Meachem himself says: ‘All observations 
show an increase of temperature in undisturbed strata of 1° F. for every 
110 feet of descent beyond 65 feet from the surface.’ ! 
Mr. W. N. Atkinson ? obtained a nearly identical rate at a new shaft 
at Baggeridge Wood, 8. Staffs ; but the circumstances were unfavourable, 
the shaft being wet, and the observations not made till about a week after 
the sinking was finished. The temperature thus found was 664° ata 
depth of 1841 feet. Assuming a surface temperature 48}°, this is an 
increase of 1° in 102 feet. The Secretary has made inquiries to ascertain 
whether these very slow increases in South Staffordshire can be due to 
steep inclination. He learms from Mr. W. N. Atkinson that the strata 
in South Staffordshire generally are very flat and nearly level. At 
Hamstead the inclination averages only one in 55 (or, according to Mr. 
Meachem, | in 19). In North Staffordshire, on the other hand, the strata 
are much contorted, and the inclinations at Glebe, Great Fenton, and 
Sneyd range from 1 in 10 tol in 5. The suggested explanation of the 
difference therefore completely breaks down. 
’ Trans. Inst. Min. Eng., vol. xxv. 1903, p. 271. 
? Q. 2295 in Report of Commission. 
