ABACUS is also used by modern writers for a table of numbers ready cast up, to expedite the operations of arithmetic. In this sense we have Abaci of addition, of multiplication, of division. This instrument for computation is, under some variations, in use with most nations, as the Greeks, Romans, Germans, French, Chinese, &c.

Grecian ABACUS, was an oblong frame, over which were stretched several brass wires, strung with little ivory balls, like the beads of a necklace; by the various arrangements of which all kinds of computations were easily made.

Roman ABACUS was a little varied from the Grecian, having pins sliding in grooves, instead of strings or wires and beads.

Chinese ABACUS, or SHWANFAN, like the Grecian, consists of several series of beads strung on brass wires, stretched from the top to the bottom of the instrument, and divided in the middle by a cross piece from side to side. In the upper space every string has two beads, which are each counted for 5; and in the lower space every string has five beads, of different values, the first being counted as 1, the second as 10, the third as 100, and so on, as with us.

ABACUS Pythagoricus, the common multiplication table, so called from its being invented by Pythagoras.

ABACUS Logisticus, is a rectangled triangle, whose sides, forming the right angle, contain the numbers from 1 to 60; and its area, the facta of each two of the numbers perpendicularly opposite. This is also called a canon of sexagesimals.

ABACUS et Palmulae, in the Ancient Music, denote the machinery, whereby the strings of polyplectra, or instruments of many strings, were struck with a plectrum made of quills.

ABACUS Harmonicus, is used by Kircher for the structure and disposition of the keys of a musical instrument, whether to be touched with the hands or the feet.

ABACUS Major, in metallurgic operations, the name of a trough used in the mines, wherein the ore is washed.