Morland multiplication machine

The Englishman Samuel Morland invented not only his addition gadget, but also a mechanized form of Napier’s rods for multiplication and addition. Only one machine has survived and is in the Instituto e Museo di Storia della Scienza, Florence. The one shown here is a replica. Morland had probably already designed the machine by 1664; it was built by Henry Sutton and Samuel Knibb around 1666. In 1673 Morland presented his machine to Grand Duke Cosimo III. He replaced Napier’s rods by circular silver discs with the digits of Napier’s rods inscribed along their circular edges so that the units and tens of the rods are opposite one another. These discs (stored along the far edge of the machine) are placed next to one another – after lifting the covering plate – on the axles at the near edge of the frame, according to the multiplicand, and are then all then processed by turning the ornamental crank at the right. An indicator with a scale in the middle of the frame, below the spare discs, shows the digit of the multiplier by counting the number of crank revolutions. The result appears in the eleven windows along the near edge of the frame between the axles, whereby each window shows a digit from the disc to its left and a digit from the disc to its right. At the end, these two numbers must be added in each window to give the result, as with Napier’s rods. The windows to the left and right of the revolution counter can be used for noting intermediate results by means of a square-shafted key. Morland publicized his machine as “Machina nova cyclologica pro multiplicatione“ in 1673 in his book “The Description and Use of Two Arithmetick Instruments“.