XIV NOTES. 



vol. xvi. Pt. III. p. 379393), the temperature of the ground at a depth of 

 three feet and more (deeper, therefore, than Boussinganlt prescribes), 85 and 

 86 Faht. ; the mean temperature of the air being stated to be 80'02 Faht. 

 Newbold's experiments (Phil. Trans, for 1845, Pt. I. p. 133) gave, at a 

 depth of one foot, at Bellary (in 15 5' lat.), 4 Faht. increase of temperature 

 from sunrise to two hours after noon ; but at Cassargode (lat. 12 29'), with a 

 clouded sky, only 1. Were the thermometers duly protected, and the ground 

 adequately screened from the direct influence of the sun's rays ? Compare 

 also J. D. Forbes, Exper. on the Temp, of the Earth at different Depths, in the 

 Edinb. Trans, vol. xvi. Pt. II. p. 189. Colonel Acosta, the meritorious his- 

 torian of New Granada, has recently made at Guaduas, on the south-western 

 declivity of the highlands of Bogota, where the mean temperature of the year is 

 74'84 F. at a depth of one foot, and in a covered space, a long series of observa- 

 tions which fully corroborate Boussingaulf's statement. Boussingault writes: 

 " Les observations du Colonel Acosta, dont vous connaissez la grande pre'cision 

 en tout ce qui inteYesse la Me'te'orologie, prouvent qne, dans Us conditions 

 d'dbri, la tempe'rature reste constante entre les tropiques a une tres-petite 

 profondeur." 



( 42 ) p. 41. On Gualgagoc (or Minas de Chota) and Micuipampa, see Hum- 

 boldt, Recueil d'Observ. astron. vol. i. p. 324. 



( 4S ) p. 41. Essai politique sur le Roy. de la Nouv. Espagne, (2 e eU) t. iii. 

 p. 201. 



(") p. 43. C. Von Baer, in MiddendoriFs Sibirischer Reise, Bd. i. S. 7. 



( 4S ) p. 44. The Merchant Fedor Schergin, head of the comptoir of the Rus- 

 so- American Trading Company, began, in the year 1828, to have a well sunk in 

 the court of a house belonging to the Company. As down to the depth of ninety- 

 six feet, which he reached in 1830, only frozen earth was found, and no water, he 

 gave up the work, until Admiral Wrangel passed through lakutsk on his way 

 to Sitka, and, perceiving the great scientific interest which attached to piercing 

 through the subterranean icy stratum, asked Mr. Schergin to continue the bor- 

 ing. In 1837, a depth of fully 382 Eng. feet had been reached, the ice still 

 continuing. 



() p. 45. Middendoi-ff, Reise in Sib. Bd. i. S. 125133. " If," says 

 Middendorff, " we exclude all cases where the depth reached falls short of 100 

 feet, because, according to experience hitherto in Siberia, all lesser depths are 

 subject to annual variations of temperature, there still remain such anomalies or 

 differences in the rate of increase of temperature that, while between 150 and 

 200 feet, it has been found so rapid as to give only fi6 English feet for an 

 increase of 1 Reaum. ; between 250 and 300 feet, the observations would give 



