Mongolia, the Tangut country, and the solitudes of northern Tibet/Volume 2/Difficulty as to Fires at Great Altitudes

DIFFICULTY AS TO FIRES AT GREAT ALTITUDES.
P. 183.

Marco Polo notices this in his account of Pamir; and a note on that passage (2nd ed. i. p. 187) gives some remarks on the subject by Humboldt, and some of the experience of my friend Col. Montgomerie, R.E.—[Y.]