ON UNDERGROUND TEMPERATURE. 



17 



value. It was also suggested that the mean temperature of the surface 

 overhead should be examined by boring. 



M. Sismonda speedily replied, stating that he fully recognized the impor- 

 tance of such experiments, and had already made arrangements with the 

 Government at Turin, and with the contractors for the railway works, to 

 have them carried out as fully and fairly as possible. Had the communica- 

 tion reached him at a time of year when he could have travelled without 

 great inconvenience, he would have gone to the spot himself; but as that 

 was now impossible, the Government Commissioner for the works, M. Salva- 

 tori, had undertaken to see the experiments carried through by employes 

 under his orders. M. Sismonda further stated that, from the commence- 

 ment of the tunnel, the Academy of Sciences of Turin had instituted a series 

 of scientific observations in it, in which observations of temperature were 

 included. The results of these observations he promised to forward as soon 

 as they were completed and tabulated. 



On the receipt of the final refusal to bore down at the bottom of Eosc- 

 bridge Colliery, inquiries were instituted as to the feasibility of executing a 

 similar operation in the deepest part of the Alpine tunnel. The contractors 

 have, however, declined to grant permission, as the operation would involve 

 additional encumbrance of the very narrow space in which their works are 

 proceeding. It appears that a length of a mile or more in the deepest part 

 of the tunnel has not yet been opened out to the full width, so that oppor- 

 tunity niay yet be given to excavate a lateral heading and bore down, if the 

 Association encourage the plan. 



Mr, G. J. Symons has repeated his observations in the Kentish Town 

 weD, at every fiftieth foot of depth, from 350 to 1100 feet, which is the 

 lowest point attainable. As the water begins at the depth of 210 feet, all 

 these observations may be regarded as unaff'ected by the influence of the 

 external air, and they have now been sufficiently numerous at each depth 

 to render further verification needless. The following are the results finally 

 adopted, and they do not diifer materially from those first published (Report 

 for 18693. 



18^ 



