The antiquity in particular of the measurement of time by the moon is demonstrated by language;( 1) even the mode of reckoning the days that elapse between the several phases of the moon, not forward from the phase on which it had entered last, but backward from that which was next to be expected, is at least older than the separation of the Greeks and Latins.
Decimal System The most definite evidence of the antiquity and original exclusive use of the decimal system among the Indo-Germans is furnished by the well-known agreement of all Indo-Germanic languages in respect to the numerals as far as a hundred inclusive.( 2) In the case of Italy the decimal system pervaded all the earliest arrangements: it may be sufficient to recall the number ten so usual in the case of witnesses, securities, envoys, and magistrates, the legal equivalence of one ox and ten sheep, the partition of the canton into ten curies and the pervading application generally of the decurial system, the -limitatio-, the tenth in offerings and in agriculture, decimation, and the praenomen -Decimus-.

Among the applications of this most ancient decimal system in the sphere of measuring and of writing, the remarkable Italian ciphers claim a primary place.

When the Greeks and Italians separated, there were still evidently no conventional signs of number.

On the other hand we find the three oldest and most indispensable numerals, one, five, and ten, represented by three signs--I, V or /\, X, manifestly imitations of the outstretched finger, and the open hand single and double--which were not derived either from the Hellenes or the Phoenicians, but were common to the Romans, Sabellians, and Etruscans.

They were the first steps towards the formation of a national Italian writing, and at the same time evidences of the liveliness of that earlier inland intercourse among the Italians which preceded their transmarine commerce.( 3) Which of the Italian stocks invented, and which of them borrowed, these signs, can of course no longer be ascertained.