On the temperature-gradients of deep bores, with special reference to those of the Balfour Bore, Cameron Bridge, Fifeshire

Abstract

The Balfour bore, after extending over a period of several years, was brought to a close on the 3rd of June 1907, at a depth of 4534 ft. Observations as to temperature were taken by Mr John Gemmell, Mining Engineer, who has kindly furnished the following particulars for communication to this Society. These observations were made in the period from Saturday, 31st August, to Tuesday, 3rd September, 1907, and thus about three months after the conclusion of boring operations. Five thermometers were used, one by Casella and four by Hume. In the case of the first mentioned, a small column of mercury is separated from the rest by means of a bubble of air. The separated part is pushed up by the expansion of the mercury in the ball, but remains stationary when the latter contracts, except when the instrument is violently shaken, and thus indicates the highest temperature which has been experienced by the thermometer. The four by Hume were on the principle of an ordinary clinical thermometer. These thermometers were afterwards tested at Kew, and allowance has been made for the errors thus found. The Hume's thermometers were enclosed in a double casing of indiarubber tubing, while the Casella's thermometer was enclosed in a thick sealed glass tube, inside which was a quantity of spirit. The thick tube has the effect of protecting the thermometer from the pressure of the water in the bore-hole, which otherwise would cause an alteration in the readings, while the spirit acts as