133 KEPORT — 1872. 



temperature could have remained for two daj'S without sensible diminution. 

 In connexion -with this question, the apparent cooling to the extent of 

 0°*4 at the depth of 6U0 metres between the first and second observation 

 demands attention, and is not very easily explained. 



If the observed temperature at 660 metres is to be talien as the normal 

 temperature, the average increase from 100 metres to that depth is at the 

 rate of 1° F. in 22-2 metres, or in 72-8 feet. If the observed tempera- 

 ture at 600 metres in the second scries is adopted, the increase from 

 100 metres to that depth is at the rate of 1° F. in 28-7 metres, or in 

 9-1-3 feet. 



The observations proposed by Messrs. Mauget and Lippmann in the para- 

 graph above quoted Avill be eminently calculated to assist in showing the 

 correct interpretation. 



Mr. G. A. Lebour, F.G.S., of II.M. Geological Survey, has furnished obser- 

 vations taken in a bore-hole executed at the bottom of South Iletton Colliery, 

 Durham. The observations were taken by Mr. J. E. Atkinson, a student at 

 the Newcastle College of Physical Science, and appear to have been carefully 

 made. Thanks are also due to the viewer of the colliery, Mr. Matthews, for 

 granting the requisite facilities. 



The hole is 2^ inches in diameter, and was bored out of the pumping 

 side of the South Hettou shaft, in order that the bore-rods might be the more 

 readily altered. The depth of the shaft is 1066 feet, that of the bore-hole 

 863 feet from the bottom of the shaft, or 1929 feet from the surface of 

 the ground. The section of the boring (not including the shaft) consists 

 of 123 alternating beds of shale and sandstone*, with occasional thin seams 

 of coal and some fire-clays. The bottom of the boring has reached a very 

 coarse white grit, which is supposed to be the topmost bed of the Millstone- 

 grit series. 



The bore was dry at the time of its execution, but has since become 

 filled with water, probably derived from the shaft above it. Streams, in 

 fact, pour down the shaft and play about the hole. 



Two thennometers, one of them an unprotected Phillips, and the other a 

 protected Negretti, were supplied by the Secretary to Mr. Lebour, as it was 

 not certainly known at that time whether the bore was dry or wet. Mr. 

 Lebour indeed believed it to be dry, but nevertheless selected the Negretti 

 thermometer, as it was thought that the Phillips could not be read off accu- 

 rately with the poor light which in the position of this bore-hole was alone 

 available. 



The following Table exhibits the results of all the observations which 

 have been taken in the bore, including three which were taken in 1869, 

 while the boring Avas going on. The boring was stopped, in the case of each 

 of these three observations, only about 20 minutes before the observations 

 were made ; and the heat due to friction appears to have produced abnormal 

 elevation of temperature, amounting to about 2° at the depth of 288 feet, to 

 about 6° at the depth of 582 feet, and to considerably more than this at 

 858 feet. The other observations in the Table are Mr. Atkinson's, taken 

 with the Negretti thermometer. 



* A complete list of the strata Las been furnished, and will be preserved by the Secre- 

 tary, with a view to future reference if required. 



