Original edition of 1830, i. 369.
See Professor Tyndall's Glaciers of the Alps, for an account of glacier-tables, sand-cones, &c. Anyone who has walked on a glacier will have noticed the little pits which any small black substance, whether a stone or a dead insect, sinks for itself in the ice.
Gilbert, Annalen, lxix. 143.
According to the latest accounts I have been able to obtain, a temperature of 29·75° F. had already been reached some years ago; the temperature, a few feet from the surface, being 14° below freezing. The soil here only thaws to a depth of 3 feet in the hottest summer. Sir R. Murchison wrote to Russia, in February last, for further information regarding this well.
Since I wrote this, Sir Roderick Murchison has applied to the Secretary of the Imperial Academy of St. Petersburg for further information respecting the investigations at Jakutsk. The Secretary gives a reference to Middendorff's Sibirische Reise, Bd. iv. Th. i., 3te Lieferung, Klima, 1861. I have only been able to find the edition of 1848-51; but in that edition, under the heading Meteorologische Beobachtungen, elaborate tables of the meteorological condition of Jakutsk are given (i. 28-49). Also, under the heading Geothermische Beobachtungen, very careful information respecting the frozen earth will be found (i. 157, &c., and 178, &c.). The point at which a temperature of 32° will be attained, is reckoned variously at from 600 to 1,000 feet below the surface.