“5. In like manner, his Lordship considers you to be entitled to commendation for the extent of geographical and general information collected in the voyage, and for the caution used in procuring it, no less than for the perspicuous and complete form in which the results have been submitted for record and consideration. The map prepared by you forms an addition to the geography of India of the first utility and importance, and cannot fail to procure for your labours a high place in this department of science.

“6. The result of your voyage in the different reports, memoirs, and maps above acknowledged, will be brought without delay to the notice of the authorities in England, under whose orders the mission was, as you are aware, undertaken. His Lordship doubts not that they will unite with him in commending the zeal, diligence, and intelligence displayed by you in the execution of this service, and will express their satisfaction at the manner in which their views have been accomplished, and the objects contemplated in the mission to Lahore fully and completely attained.

“I have the honour to be, &c.
(Signed) “H. T. Prinsep,
“Secretary to the Governor-general.”

A
MEMOIR ON THE INDUS,
AND
ITS TRIBUTARY RIVERS
IN
THE PUNJAB.

NOTICE
REGARDING
THE MAP OF THE INDUS.

A new map of the Indus and Punjab Rivers from the sea to Lahore seems to require some notice explanatory of its construction, and I have to offer the following observations on that subject:—

The River Indus, from the southern direction in which it flows in its progress to the ocean, presents few difficulties to the surveyor, since an observation of latitude serves to fix the daily progress in the voyage, and its comparatively straight course admits of easy delineation. The map rests on a series of observations by the stars. I should have preferred altitudes of the sun; but, with a people so suspicious as we encountered, it was impossible to use an instrument in daylight, and I should have required to halt the fleet twice to procure equal altitudes, since the sun was south of the equator during the voyage. Many of the large places, such as Tatta, Sehwun, Ooch, Mooltan, &c., where we necessarily halted, have been laid down from a mean of eight or ten stellar observations.

The longitude and general delineations in the curvature of the river rest on a minute protraction of its turnings, observed with care every half hour, and sometimes oftener, with the approved compass by Schmalcalder. The attention given to this important portion of the undertaking may be imagined, when I state that my field books exhibit, on an average, twenty bearings each day from sunrise to sunset. I was early enabled to rate the progress of the boats through the water, by timing them on a measured line along the bank, and apportioned the distance to the hours and minutes accordingly. We could advance, I found, by tracking, or being pulled by men, at one mile and a half an hour; by gentle and favourable breezes at two miles, and by violent winds at three miles an hour; while any great excess or deficiency was pointed out by the latitude of the halting place.

The base on which the work rests, is the towns of Mandivee and Curachee: the one a seaport in Cutch, and the point from which the mission started; the other a harbour in sight of the western mouth of the Indus, which we saw before entering the river. Mandivee stands in the latitude of 22° 50´, and Curachee in 24° 56´ north; while their longitudes are respectively in 69° 34´, and 67° 19´ east, as fixed, in 1809, from the chronometers of the Sinde mission by Captain Maxfield.

Assuming these points as correct, the line of coast intermediate to them has been laid down from my own surveys in Cutch; while that of Sinde rests on observations of the sun’s altitude at noon and the boats’ daily progress, determined by heaving the log hourly. We sailed only during the day, and at all times along shore, often in a small boat, and were attended by six or eight pilots, who had passed their lives in the navigation of those parts.