The question has been raised, whether there may not exist behind the southernmost more or less perfectly measured chain, other still greater elevations. Colonel George Lloyd, who in 1840 edited the important observations of Captain Alexander Gerard and his brother, entertains an opinion that in the part of the Himalaya which he calls somewhat vaguely “the Tartaric chain,” (meaning therefore in north Thibet towards the Kuen-lün, and perhaps in Kailasa of the sacred lakes, or beyond Leh) there are summits of from 29000 to 30000 English feet,--one or two thousand feet higher therefore than the Dhawalagiri. (Lloyd and Gerard, Tour in the Himalaya, 1840, vol. i. p. 143 and 312; Asie Centrale, T. iii. p. 324.) So long as actual measurements are wanting, one cannot decide respecting such possibilities; as the indication, from which the natives of Quito, long before the arrival of Bouguer and La Condamine, recognised the superior altitude of the Chimborazo (namely, from the portion of its height above the region of perpetual snow being greater than in any of the other mountains), might prove very deceptive in the temperate zone of Thibet, where radiation is so active in the table-land, and where the lower limit of perpetual snow does not form a regular line at an equal elevation, as it does in the tropics. The greatest elevation above the level of the sea ever attained by human beings on the declivity of the Himalaya, is 3035 toises, or 18210 Parisian, or 19409 English feet, reached by Captain Gerard, with seven barometers, on the mountain of Tarhigang, a little to the north-west of Schipke. (Colebrooke, in the Transactions of the Geological Society, vol. vi. p. 411.) This happens to be exactly the same height as that reached by myself on the 23rd of June, 1802, and thirty years later by my friend Boussingault, on the 16th of December, 1831, on the declivity of the Chimborazo. The unattained summit of the Tarhigang is, however, 197 toises, or 1260 English feet, higher than that of the Chimborazo.