TEMPERATURE OF THE EARTH.

Dominion, Volume 1, Issue 216, 5 June 1908, Page 10

TEMPERATURE OF THE EARTH.

INTERESTING INVESTIGATIONS. ■(BY TELEGRAPH. —SPECIAL CORRESPONDENT).. Oliristchurch, Juno 4. The Council of the Canterbury Philosophical Institute has drawn up a scheme of investigations into tbo temperature of the earth in connection with the Otira tunnel. Tho scheme is laregly on tho lilies of tho schemes adopted in connection with tho great Swiss tunnels, and it is expccted that as tho boring proceeds some very valuable knowledgo will .lio obtained. . < ~ Mr. E. G. Hogg, president of (tho Institute, in a paper v read before that body last night, said tho accumulation of observations of temperature might eventually throw considerable light on the structure of a mountain chain, and t'jho.' manner in which the mountain mass was related to . tho .interior of tho earth. To ascertain the surface reek temporaturo the observation stations would be selected as nearly as possible over tho line tho tunnel would (take. At each station a vertical holo six feet deep would be drilled in tho solid rock to hold a hollow iron tube in which a slow-reading thermometer would be placed. These thermometers, would be read each fortnight, and from the records obtained in this manner over a space ,of three or four years \ tho rock temperctturo at a depth of about six feet from tho surface would bo plotted and its value free from the disturbing periodic variation would be determined. It would be tho first occasion on which work of that nature was attempted on any serious scale in Now Zealand. Within tho tunnel bore holes would be drilled at distances of 200 yards from each other in the sido of tho tunnel as near as would bo safe to tho advancing face of tho tunnel. Tho boreholes would bo six feet deep, slightly inclined to tho liorizon to allow water percolating into them to escape. Slow acting thermometers for the most part would be used, but in certain of the bores maximum and minimum thermometers would also be inserted. After a suitable time had elapsed to allow of the dispersion of tho heat generated by tho boring tool to be dissipated, tho thermometer would be placed in position, and tho holo securely stopped with roclt and sand. Headings would be taken at the end of 2*l, <18, and 60 hours after the first insertion of tho thermometer. Th<\. institute had good reason to believe that it would secure a series of accurate observations, which would bo of great scientific value. It had been assured of tho cordial co-operation of Messrs. M'Leaii Brothers, tho contractors for the tunnel, in carrying out the scientific work successfully.