ROMAN NUMERALS

There are several points connected with the subject of numerals that are important in the history of practical arithmetic, to which neither scientific men nor antiquaries have paid much attention. Yet if the principal questions were brought in a definite form before the contributors to the "NOTES AND QUERIES," I feel quite sure that a not inconsiderable number of them will be able to contribute each his portion to the solution of what may till now be considered as almost a mystery. With your permission, I will propose a few queries relating to the subject, 1. When did the abacus, or the "tabel…