by various authors

“ To understand the use of this abacus, the calculator must be supposed sitting before one of its long sides, and putting counters into the spaces between the marked lines. Each space represents an order of numerals, the space on the right hand being intended for units, the next space for tens, the next for hundreds, and so on. The numbers belonging to the first four of each series are put on that side of the bisecting line which is nearest the calculator; those over 5 are put beyond it. ”

“ Caption: "Roman Abacus or Calculating Table."] The Roman abacus (figured here from the Kircherian Museum at Rome) was on the same system. It is divided into eight lower and eight higher (somewhat shorter) groves: there is [p. 3] also a ninth lower groove, without an upper groove to correspond. Four sliding buttons are attached to each lower groove except the eighth, which has five: each upper groove has one button. ”

“ The two additional characters in the left-hand series are [drachm5000] = 5000 ( [drachm5] with [drachm1000] inscribed) , and Τ = talent (of 6000 drachmas) ; so that the lowest and highest money units are at the two ends of the scale. ”