296 REPORTS OF RE.SEARCH COMMITTEES. 



As soo'n as this was recognised, thermometers were installed in 

 each of the pendulum ohambeTs, and these are nc«w read when the 

 photographic papers are changed. It is hoped by the comparison 

 of the temperature records for each instrument that the move- 

 ments due to seasonal changes in tem]>erature will be able to be 

 discriminated, and the deflections due to the water-load be deter- 

 mined. 



This seasonal movement in the earth's crust opens up a new 

 line of investigation, and it should be possible to obtain from the 

 records important information with regard to the heat conduc- 

 tivity of the rocks, and also of their co-efficient of expansion, and 

 possibly, also, some information with regard to their rigidity. 



It is, of course, essential for this work, as well as for the main 

 investigation, to have a detailed geological and topographical 

 survey of the area. This work was taken up' about twoi years ago, 

 and, though far from completion, has yielded important informa- 

 tion with regard to the lithological characters and rock structures 

 of the area under investig"ation. This work is now being carried 

 forward hand in hand with the ]>endulum observations. 



The ineasurement of the records is not yet up to date, but is 

 most advanced in the case of the Heidleburg pendulum. This 

 pendulum has, on the whole, given the most satisfactory results, 

 and is that which is best placed for recording changes in the water- 

 load. It is, therefore, very necessary for the complete success of 

 the investigation toi maintain this instrument with the others until 

 the full water-load is available for measurement. 



In October last a communication M'as received from Professor 

 Kruger requesting the return of the Heidelburg pendulum. 

 Professor Sir Edgeworth David replied, pointing out that the pen- 

 dulum was still in use, and that it was still required for the 

 investigation. He asked that it be loaned for a further period. 

 This request has been granted. 



As may be seen by reference to page 6 of the j^rogress report 

 bv the Permanent Honorary Secretary, " Sums totalling £155 

 have been paid to this Committee in order to provide apparatus 

 and current expenses for the work, in anticipation of the approval 

 of the General Council of the Association of the sum of £K)5, 

 £50 having been voted at the Melbourne meeting." 



The Determination of Gravity in Certain Critical Localities 

 Committee, therefore, fonnally requests that the additional sum 

 of £105 be voted in confirniation. 



The Committee has to report that the funds above mentioned 

 have now been exhausted, and begs to apply for an additional 

 S^rant of £50. 



