2 INTRODUCTORY
If this fact is considered in addition to the great extension of the ground surveyed, the hope seems justified that these new maps will for some time to come
Purpose of Memoir. serve as a main source of cartographical reference for an important
portion of Central Asia, which, by the physical conditions of its present and by its great rôle in the past, as the meeting place of the ancient civilizations of India, China and the West, is attracting more and more interest both from the geographer and the historical student. It has hence appeared appropriate to accompany the issue of these maps by a memoir recording needful information as to the history and extent of those successive surveys; the character of the materials furnished by them ; the methods adopted for the construction of the maps and the representation of topographical data in them.