that the ceremony of knocking them out, like others practised in Australia, is very partially diffused.  The rite of circumcision, for instance, is only performed at King’s Sound, on the west side of the Gulf of Carpentaria, and near the head of the Australian bight on the south.  Mr. Eyre, who discovered the existence of the rite on the last-mentioned part of the continent, infers that the natives of the places I have mentioned must have had some communication with each other through the interior; but it is possible that at a distant period of time, circumcision may have been very generally practised, and that having become gradually disused, the custom is now only preserved at two or three points, widely separated from each other.  I do not advance this as a theory, but simply as a suggestion, as there is some difficulty in supposing communication to have taken place across the continent.

Migration of the natives.

Some light may be thrown on the migration of the aboriginal inhabitants of Australia, by tracing the parts of the coast on which canoes are in use.  It has already been mentioned, that we had not seen any westward of Clarence Strait, neither were they in use in the bottom of the Gulf of Carpentaria, nor on the south coast.* By the assistance of these and similar facts, we may hereafter be enabled to discover the exact direction in which the streams of population have flowed over the continent.  But I am not prepared to agree entirely with Mr. Eyre when he concludes, as I have stated, from the fact of the rite of circumcision having been found on the south and north-west coasts, and on the Gulf of Carpentaria, that there exists any peculiar connection between the tribes inhabiting those several points.  This enterprising traveller moreover thinks that the idea he has started goes far towards refuting the theory of an inland sea, another presumption against which he maintains to be the hot winds that blow from the interior.

(Footnote.  An inference may be drawn from the parts of the shore on which canoes are in use, to show that the migrations of the natives, so far southwards, have been along the coast.  The raft they use is precisely the same in make and size on the whole extent of the North-west coast.)

Theory of an inland sea.

I confess that the theory of an inland sea has long since vanished from my mind, though I base my opinion on reasons different from those of Mr. Eyre.  The intercourse between natives of opposite sides of the continent (though it is certainly possible) has never been established, and while it remains hypothetical, cannot be adduced to overthrow another hypothesis.  The existence of hot winds also blowing from the interior is not conclusive, as we had, when in the Gulf of Carpentaria, very cold winds coming from the same direction.  We know, however, that the temperature of winds depends much on the nature of the soil over which they sweep, for instance, in a cold clayey soil, the radiation of heat is very rapid.