NOTES. Xlll 



von Oeynhausen. Compare Kosmos, Bd. i. S. 416, Anm. 94, and S. 426, Anm. 8 

 (English edition, Notes 124 and 138) ; also Bischof, Lehrbuch der chem. und 

 phys. Geologie, Bd. i. Abth. i. S. 154 163. In absolute depth, the boring at 

 Mondorf, in the Grand Duchy of Luxembourg (2066 Fr. feet), comes next to 

 that of Neu-Salzwerk. 



C 5 ) p. 37. Kosmos, Bd. i. S. 426 (English edition, p. 406), and Me'moires 

 de la Socie'te d'Hist, Naturelle de Geneve, t. vi. 1833, p. 243. The comparison 

 of a great number of Artesian wells in the neighbourhood of Lille with those of 

 St. Ouen and Geneva, might lead us to infer a more considerable influence of 

 the conducting power of the strata, if we could be satisfied that the data were 

 all equally accurate. (Poisson, The'orie mathe'matique de la Chaleur, p. 421.) 



(*) p. 37. In a table of 14 borings, of above 100 metres in depth, from the 

 most different parts of France, Bravais, in his instructive encyclopedic memoir, 

 " Patria," 1847, p. 145, cites nine in which the depth corresponding to an in- 

 crease of temperature of 1 centigrade falls between 27 and 39 metres, varying 

 from 5 to 6 metres on either side of the mean (32 m ) given in the text. (Com- 

 pare also Magnus in Poggend. Ann. Bd. xxii. 1831, S. 146.) On the whole, 

 the increase of temperature appears to be more rapid in Artesian wells of very 

 small depth ; although, in this respect, the very deep wells of Monte Massi in 

 Tuscany, and Neuffen in the north-western part of the Swabian Alps, form 

 remarkable exceptions. 



( 37 ) p. 38. Quetelet, in the Bulletin de 1'Acad. de Bruxelles, 1836, p. 75. 



( ffl ) p. 38. Forbes, Exper. on the Temperature of the Earth at different 

 Depths, in the Transactions of the Royal Society of Edinburgh, vol. xvi. 1849, 

 Pt. II. p. 189. 



(") p. 39. All the figures relating to the temperature of the Caves de 1'Ob- 

 servatoire are taken from Poisson 's The'orie Mathe'matique de la Chaleur, p. 415 

 and 462. On the other hand, the Annuaire mete'orologique de la France of Mar- 

 tins and Haeghens, 1849, p. 88, contains different corrections of Lavoisier's sub- 

 terranean thermometer, by Gay-Lussac. On the mean of three readings (June to 

 August), that thermometer gave 12-193, when Gay-Lussac found the tempera- 

 ture ll-843 ; the difference therefore being 0'350. 



(*) p. 39. Cassini, in the Mem. de 1'Acad. des Sciences, 1786, p. 511. 



( 41 ) p. 41. Boussingault, " Sur la profondeur a laquelle on trouve dans la 

 Zone torride la Couche de Temperature invariable," in the Annales de Chimie et 

 de Physique, t. liii. 1833, p. 225 247. John Caldecott, astronomer to the 

 Rajah of Travancore, and Captain Newbold in India, have objected to the me- 

 thod recommended in this memoir, and confirmed by so many exact results 

 obtained in South America. Mr. Caldecott found at Trevandrum (Edinb. Trans. 



