The laborious research, in the course of which these data were accumulated, commenced in 1806, when the author was attached to the embassy sent, at the close of the Mahratta wars, to the court of Sindhia. This chieftain’s army was then in Mewar, at that period almost a _terra incognita_, the position of whose two capitals, Udaipur and Chitor, in the best existing maps, was precisely reversed [3]; that is, Chitor was inserted S.E. of Udaipur instead of E.N.E., a proof of the scanty knowledge possessed at that period. In other respects there was almost a total blank. In the maps prior to 1806 nearly all the western and central States of Rajasthan will be found wanting. It had been imagined, but a little time before, that the rivers had a southerly course into the Nerbudda; a notion corrected by the father of Indian geography, the distinguished Rennell.[1.5] This blank the author filled up; and in 1815, for the first time, the geography of Rajasthan was put into combined form and presented to the Marquess of Hastings, on the eve of a general war, when the labour of ten years was amply rewarded by its becoming in part the foundation of that illustrious commander’s plans of the campaign. It is a duty owing to himself to state that every map, without exception, printed since this period has its foundation, as regards Central and Western India, in the labours of the author.[1.6] =The Author’s Surveys.=—The route of the embassy was from Agra, through the southern frontier of Jaipur to Udaipur. A portion of this had been surveyed and points laid down from celestial observation, by Dr. W. Hunter, which I adopted as the basis of my enterprise. The Resident Envoy[1.7] to the court of Sindhia was possessed of the valuable sketch of the route of Colonel Palmer’s embassy in 1791, as laid down by Dr. Hunter, the foundation of my subsequent surveys, as it merited from its importance and general accuracy. It embraced all the extreme points of Central India: Agra, Narwar, Datia, Jhansi, Bhopal, Sarangpur, Ujjain, and on return from this, the first meridian of the Hindus, by Kotah, Bundi, Rampura (Tonk), Bayana, to Agra. The position of all these places was more or less accurately fixed, according to the time which could be bestowed, by astronomical observation [4]. At Rampura Hunter ceased to be my guide: and from this point commenced the new survey of Udaipur, where we arrived in June 1806. The position then assigned to it, with most inadequate instruments, has been changed only 1´of longitude, though the latitude amounted to about 5´.