362 DR. LEICHARDT'S OVERLAND JOURNEY 
habited parts of the colony it appears that this dessication is 
not dependant upon colonisation, upon the clearing of the 
ground, and the increase of stock, though there is no doubt 
that the latter must make a great impression on limited 
water-holes not supplied by springs. We are, therefore, 
compelled to look for the cause in some until now unknown 
change of the atmosphere which may be periodical, and allow 
us to hope that the Australian continent will be again favoured 
with a series of more rainy seasons. 
Dr. Leichardt concluded his lectures by laying before his 
audience the plan of an expedition on which lie intended to 
start in October last. Captain Sturt's expedition having 
shown that the interior, in the longitude of the head of the 
gulf, is a desert at least to latitude 24? S. where the explorer 
was compelled to return. He considered therefore that 1t 
would not be advisable to attempt to cross the continent in 
that or in a higher latitude; he therefore proposed to pro- 
ceed at once to latitude 23° S. where he found the Mac- 
kenzie and Peak Range, during his last journey ; and as the 
Mackenzie was well supplied with water, he intended to 
follow it up to its sources, which he expected to find about 
80 or 100 miles to the westward of the spot where he first. 
came on the river. He would then be able to ascertain - 
whether the western branches of the supposed watershed £0 — 
to the southward to join the system of the Darling 9T —— 
whether they turn to the northward, and form the sources Of — 
the larger rivers of the head of the gulf of Carpentarià- 
Should the latter be the case, and should the country bé — 
sufficiently well watered, he would of course proceed to the 1d 
. westward, keeping the same latitude, and try to reach the — 
waters of the north-west coast. But should want of water — 
= not allow him to continue his journey to the westward, OT - 
_ even to the northward, he would retrace his steps down the 
. Mackenzie, and follow the track of his last journey to ™ 
Burdekin, where it is joined by the Clarke, in lat. 19° 12! 5+ 
He then proposed to follow the latter river, and expected 
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