256 REPORT— 1873. 



The well Is full of water to within 24 feet of the surface of the ground, 

 and is tubed with a 9-inch iron tube for about 90 feet, the top of this tube 

 being about 22 feet below the surface of the grouud. The upper portion of 

 the pipe is surrounded by a bricked well, into which there is a drain coming 

 from under two Cornish boilers close to the well ; and the water in this 

 bricked well occasionall}^ rises so high as to overflow into the pipe. This is 

 probably the cause of the high temperature recorded at 3 feet below the 

 water-surface. There would appear to be some error in the first observation 

 at 283 feet; and if this be rejected, an increase of about 1| degree is shown 

 in descending from the depth of 100 feet to that of 283 feet. 



The source of the water-supply, which is extremely abundant, is unknown, 

 the only strong spring known to exist in the unchoked portion of the well 

 being in the sand at the depth of only 30 feet. The circumstances are clearly 

 not favourable for deducing any certain inferences regarding the increase of 

 temperature downwards in the neighbouring soil. 



The arrangements for further observations of temperature in the Mont- 

 Cenis tunnel are now in the hands of Father Denza, of Moncalieri, near 

 Turin, who wrote to the following effect in April of the present year : — 



" Every thing was ready for undertaking the work in the course of last 

 year, when unexpected circumstances over which we had no control obliged 

 us to suspend it. It is now our intention to commence work in the summer 

 on which we are now entering, when I shall determine the temperature, for 

 which observations the instruments are all in order. The thermometrical 

 observations will be made in the interior of the tunnel at various depths, and 

 accompanied by others in the open air on the slope of the mountain accord- 

 ing to a fixed plan." 



Another Alpine tunnel has been commenced (in the neighbourhood of the 

 St.-Gothard pass), which Avill be both longer and deeper than that of Mont 

 Cenis. It has been pierced for a distance of about 300 metres at each end — 

 namely, at Geschenen, about miles from Audermatt on the Swiss side, and at 

 Airolo on the Italian side. The engineers at the Geschenen end (which waa 

 recently visited by the Secretary) keep a record of the air-temperature in the 

 workings. This is found to be higher by 3° Cent, at the distance now reached 

 than it was in the earlier portion of the tunnel ; but no observations of rock- 

 temperature have as yet been made. 



Application has recently been made for observations in some of the deepest 

 mines on the continent of Europe ; and in three instances a favourable answer 

 has been received. Observations may accordingly be expected from the 

 mines of the Societe Cockerill at Seraiug, near Liege, from the mines at 

 Anzin in the Departement du Word, and from some of the deepest mines in 

 Bohemia. The Secretary desires to acknowledge his obligations to M. Delesse 

 of the School of Mines at Paris, M. Sadoine of Seraing, M. de Marsilly of 

 Anzin, and Prof. Zenger of Prague. 



It is understood that numerous observations have been madeduring the past 

 year with the thermometers sent to Australia. The oificial report, however, 

 has not been as yet received. 



The Committee have learned with pleasure that a series of experiments have 

 been commenced, by Professor Alexander Herschcl and Mr. Lebour, on the 

 conductivity of difi'ereut species of rock — a subject intimately connected with 

 the inquiry in which the Committee are engaged, and one respecting which 

 additional information is greatly needed. 



