Thus there still remained a vast unknown
expanse right in the heart of the interior covering 150,000 square miles,
bounded on the North by Warburton's Great Sandy Desert, on the South by
Giles's Desert of Gravel (Gibson's Desert), on the West by the strip
of well-watered country between the coast and the highland in which the
rivers rise, on the East by nothing but the imaginary boundary-line
between West and South Australia, and beyond by the Adelaide to Port
Darwin Telegraph Line.
To penetrate into this great unknown it would be necessary first to pass
over the inhospitable regions described by Wells, Forrest, and Giles, and
the unmapped expanses between their several routes - crossing their tracks
almost at right angles, and deriving no benefit from their experiences
except a comparison in positions on the chart, should the point of
intersection occur at any recognisable feature, such as a noticeable hill
or lake.
Should the unexplored part between Giles's and Warburton's routes be
successfully crossed, there still would remain an unexplored tract 150
miles broad by 450 long before the settlements in Kimberley could be
reached, 1,000 miles in a bee-line from Coolgardie. This was the
expedition I had mapped out for my undertaking, and now after four
years' hard struggle I had at length amassed sufficient means to carry it
through.
