Burnes, Alexander: Travels into Bokhara: containing the narrative of a voyage on the Indus from the sea to Lahore, ... and an account of a journey from India to Cabool, Tartary and Persia ; performed by order of the supreme government of India, in the years 1831, 32, and 33 (Band 1) (London, 1835)

189

NOTICE

REGARDING THAT PART OF THE MAP WHICH
RELATES TO 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 1 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 encoun-
tered, 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 curv-
ature of the river rest on a minute protraction of its
turnings, observed with care every half hour, and some-
times oftener, with the approved compass by Schmal-
calder. The attention given to this important portion