which may be considered as the general property of mankind.
The occurrence or absence of gestures as an aid or substitute for speech does not, as far as I can ascertain, depend on social status, or the locality in which a tribe lives. Yet, so far as I can venture to form an opinion from my own observations, and from the statements made to me by correspondents, the use of sign language is more common in Central and North-eastern Australia than in the South-eastern quarter of the Continent.
The reason for this may perhaps be found in the vast extents of open country, plains, sandhills, and stony tracts which occur in the interior of Australia, as, for instance, in the Lake Eyre basin.
A stranger is seen there from afar off, and can be interrogated at a safe distance by gesture language as to who he is, where he comes from, and his intentions. When I first saw some of the Cooper's Creek blacks, I was struck by their use of gestures, at a safe distance, and which I took to be either a defiance or a command to depart. In reality they were the sign for peace and the sign for interrogation as to our destination, or as to our reason for being there. Afterwards, when I became better acquainted with them, I came to see that these gestures were part of a complete system of hand signs, by which a person might be interrogated, informed, welcomed, or warned. In the coastal regions or in the forest-clad mountain ranges which lie alongside the Great Dividing Range, separating the coast lands from the interior, such would not be the case, and gesture language could not be made use of at a distance excepting in rare cases.
I venture this supposition, but without laying much stress upon it.
The different degree in which gesture language is made use of may be best seen by taking a few illustrations from tribes within my knowledge.
The Dieri have a very full code of signs which suffice for ordinary needs of communication. A widow is not permitted to speak until the whole of the white clay which
