398 Scientific Intelligence — Geology. 



depth, J. c, the depth below the level of the sea. The greatest re- 

 lative depth that has been reached is, perhaps, the bore at New 

 Salzwerk, Minden, in Prussia. In June 1844, it was exactly 1844 J 

 Parisian feet ; the absolute depth was, however, 2094|- Par. feet. 

 The temperature of the water in the deepest bore was 32*7° €• 

 (90-8'^ F.) which, assuming 9'6° C. as the mean temperature of the 

 air, gives a rise of 1-6° for 29'6 metres (upwards of 97'6 feet Eng- 

 lish). The Artesian well of Grenelle, at Paris, is only 1683 feet 

 in absolute depth. From the accounts of the missionary Imbert 

 from China, the depth of our Artesian wells is far sui'passed by that 

 of the fire-spring, Ho-tsing, which yields inflammable gas, employed 

 in salt boiling. In the Chinese province Szii-tschuan, these fire- 

 springs are said very commonly to reach a depth of from 1800 to 

 2000 feet ; and at Tseu-lieu-tsing (place of perpetual flux) a Ho- 

 tsing bored with the rod in the year 1812, is reported to extend to 

 the depth of 3000 feet (Humboldt, Asie Centrale, t. ii., p. 521 

 and 525 ; Annales de I'Association de la Propagation de la Foi, 

 1829, No. 16, p. 369.) The relative depth attained at Monte Massi, 

 in Tuscany, south from Volterra, according to Matteucci, is about 

 1175 feet. The bore at New Salzwerk approaches very nearly in 

 relative depth the coal pit at Apendale, Newcastle-under-Lyme 

 (Staffordshire). There the works are carried on 725 yards, or 2045 

 French feet, under the suiface (Th. Smith, The Miner's Guide, 

 1836, p. 160). Unfortunately, the height of the ground above the 

 level of the sea is not accurately ascertained. The relative depth 

 of the Monkwearmouth pit, near Newcastle-on-Tyne, is only 1404 

 feet (Phillips, Philos. Mag. vol. v., 1834, p. 446) ; that of the 

 Esperance pit, at Liege, 1271 ; and that of the lately-worked pit 

 Marihaye, at Val St. Lambert, is 1157 feet. The greatest absolute 

 depths to which man has penetrated are in mines that are either 

 among lofty mountains or in mountain-valleys, so much raised above 

 the sea level, that this has either not been reached at all, or has only 

 been surpassed by a very small quantity. 



The Eselschacht at Kuttenberg, Bohemia, before it was abandoned, 

 had reached the enormous depth of 3545 feet (Schmidt, Berggesetze, 

 Bd. 1, S. 32). At St Daniel, and at Geist, on the Rohrerbuhelj 

 the works, in the 16th century, were 2916 feet deep. A drawing of 

 these workings of the year 1539 is still preserved. (Joseph Von 

 Sperges, Tyroler Bergwerks-Geschichte, S. 121. See also Hum- 

 boldt, Gutachten Uber Heranti'eibung des Meissner StoUens in die 

 Freiberger Erzrevier, published in Herder iiber den jetzt begon- 

 nenen Erbstollen, 1838, S. 124). It may be imagined that informa- 

 tion of the extraordinary depth of the workings at Rohrerbiihel had 

 reached England at an early period, for in Gilbert's work, De Mag- 

 nete, I find the statement that man had penetrated from 2400 to 

 3000 feet into the bowels of the earth. 



The absolute depth of the mines in the Saxon Erzgebirge are 1824 



