John Napier
The direct method of multiplying is old, as a matter of fact, the first mechanical means employed for multiplying worked by the direct method. But its combination with recording and typewriter mechanism invented by Hopkins was new.
Napier’s bones first direct multiplier
Napier, in 1620, laid the foundation of the mechanical method of direct multiplication when he invented his multiplying bones. The scheme of overlapping the ordinal places is shown in the diagonal lines used to separate units from the tens in each multiple of the nine digits ([see illustration, page 179]), thus providing a convenient means by which the ordinal values may be added together.
First direct multiplying machine
The first attempt to set Napier’s scheme to mechanism that would add and register the overlapping ordinal values was patented by E. D. Barbour in 1872. [See reproduction of patent drawings] on opposite page.
The Barbour Multiplier
The accumulator mechanism of the Barbour machine, including the numeral wheels and their devices for transferring the tens, is mounted in a sliding carriage at the top of the machine ([see Fig. 1]), which may be operated by the hand-knob.
Description of Barbour Multiplier