t apparent.

Any number system which passes the limit 10 is reasonably sure to have
either a quinary, a decimal, or a vigesimal structure. A binary scale
could, as it is developed in primitive languages, hardly extend to 20, or
even to 10, without becoming exceedingly cumbersome. A binary scale
inevitably suggests a wretchedly low degree of mental development, which
stands in the way of the formation of any number scale worthy to be
dignified by the name of system. Take, for example, one of the dialects
found among the western tribes of the Torres Straits, where, in general,
but two numerals are found to exist. In this dialect the method of counting
is:[169]

1. urapun.
2. okosa.
3. okosa urapun = 2-1.
4. okosa okosa = 2-2.
5. okosa okosa urapun = 2-2-1.
6. okosa okosa okosa = 2-2-2.

Anything above 6 they call _ras_, a lot.

For the sake of uniformity we may speak of this as a "system." But in so
doing, we give to the legitimate meaning of the word a severe strain. The
customs and modes of life of these people are not such as to require the
use of any save the scanty list of numbers given above; and their mental
poverty prompts them to call 3, the first number above a single pair, 2-1.
In the same way, 4 and 6 are respectively 2 pairs and 3 pairs, while 5 is 1
more than 2 pairs. Five objects, however, they sometimes denote by
_urapuni-getal_, 1 hand. A precisely similar condition is found to prevail
respecting the arithmetic of all the Australian tribes. In some cases only
two numerals are found, and in others three. But in a very great number of
the native languages of that continent the count proceeds by pairs, if
indeed it proceeds at all. Hence we at once reject the theory that
Australian arithmetic, or Australian counting, is essentially peculiar. It
is simply a legitimate result, such as might be looked for in any part of
the world, of the barbarism in which the races of that quarter of the world
were sunk, and in which they were content to live.

The following examples of Australian and Tasmanian number systems show how
scanty was the numerical ability possessed by these tribes, and illustrate
fully their tendency to count by twos or pairs.

MURRAY RIVER.[170]

1. enea.
2. petcheval.
3. petchevalenea = 2-1.
4. petcheval peteheval = 2-2.

MAROURA.

1. nukee.
2. barkolo.
3. barkolo nuke = 2-1.
4. barkolo barkolo = 2-2.