'Report by Mr G P Tate, Extra Assistant Superintendent, Survey of India, in charge of the survey detachment with the Seistan mission, 1903-05.' [‎3v] (6/16)

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The following is a list of the maps drawn >
Map of Seistan, scale i"=i mile 1903. Boundary from B. P. 52 to B.P. 65,
scale i"=i mile, reduced from the original survey on the scale 2' = !mile
by pentagraph, 1904.
General map of Seistan and country adjoining, scale i"=4 miles, 1903.
General map in four sheets, i' / =4 miles, 1905.
This last named map was sent for publication through the Foreign Office
in the current year. It has been carefully drawn with a view to be of service in
compiling the regular standard sheets on that scale, into which the information
would fall.
The hills in these sheets were to be represented in brown, and they have been
drawn separately on No. 5 drawing paper for this purpose, as well as all canals
and interior detail of the Hamun which were to be represented in blue colour.
The outline, names, and other details were to be reproduced in black.
The hill shading A method of showing the shape of the land on a map by shading slopes as though they were being illuminated by the sun. on those sheets was executed with horizontal hachures Lines drawn on a map to indicate the direction and steepness of slope. , and
every pillar of the boundary laid down from the Koh-i-Malik Siah in the south
to the Koh-i-Malik Siah to the north has been represented in the appropriate
sheets of the latest map on the scale of i "=4 miles.
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The compilation sheets have been compiled personally by me, and they
can be taken as originals as far as they go, having been carefully looked
over.
The western branch of the Helmand, the Rud-i-Pariun, has been surveyed
on the scale of 2 // =i mile, and this survey is authoritative for an average width
of | mile on the right and left banks. Within these limits conflicting detail
ought to be adjusted on the large scale detail.
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A series of experiments made for the purpose, showed the average magnetic
variation for Seistan, the delta, and the adjoining dashts, to be 3 0 E. In the
Hamun area, between B. P. 70 and the north terminal point of the boundary
between Afghanistan and Persia, there were however considerable local varia
tions, owing to which the alignment on the straight line of the boundary could
not be carried on when the terminal point was obscured by bad weather except
by theodolite traverse. The magnetic variations were as much as 15'the
sign being—. This was not remarkable as the floor of the Hamun is alluvial
soil, composed by rocks of all ages and formations having been ground down,
the most finely divided portions of which have in the course of countless
ages been washed down by the rivers which enter the Hamun and deposited
as soil in the basin of this lake.
Across the dasht, over which the straight line passed from the Koh-i-
Malik Siah to the bifurcation of the Rud-i-Seistan and the Helmand, there were
also considerably greater local variations of the same sign as those which
were found to exist in the basin of the Hamun.
When the alignment of the pillars towards the Koh-i-Malik Siah was
instituted in September 1904, there was a period of bad weather, during
which, in order to push on the work, the pillar sites were laid down by means
ot magnetic bearings. Owing to the local disturbances, the work had to be
redone with a theodolite.
During this realignment, it was discovered that a good many of the pillars
could be dispensed with, and so those pillars which did not need to be rebuilt