History of Computers and Computing, Calculating tools, Gadgets, Leonard Stowe

Key Points:

  • Although Leonard Stowe was from New Zealand, he obtained patents for his devices in other countries across the globe, such as Germany and the British Isles.
  • Furthermore, Stowe’s adding machine did receive high regards and an honorable mention internationally in the year 1881 at an exhibition in Australia.
  • Leonard Stowe’s adding machine mostly function with cylinder and rollers, which showed figures to help calculate totals.
Leonard Stowe
A Portrait of Leonard Stowe.

Leonard Stowe

In the late 1870s the government clerk from Wellington, New Zealand, Leonard Stowe (see biography of Leonard Stowe) devised an adding machine, which he patented in 1880 in Great Britain and Germany (patent Nr. DE11907). The English patent for Stowe’s Patent Calculating Machine (see the lower patent drawing) was assigned to Stowe Brothers, London.

A working model of the machine was exhibited at the International Exhibition of 1881 in Australia, and there it happened to received honorable mention for its design and operation.

The patent drawing of Locke Adder
The patent drawing of Leonard Stowe’s adding machine.

The patent drawing of Leonard Stowe’s adding machine.

Leonard and Jane
Leonard Stowe and his wife Jane Stowe (Greenwood) in the early 1870s (Image courtesy of Marlborough Museum, Marlborough Historical Society Inc.).

The machine of Stowe consists of a number of cylinders, or rollers, with figures printed thereon, zero or naught being represented by a red square. To the left of the cylinders are a number of indicators, each of which records every perfect revolution of its corresponding cylinder.

To place the machine ready for work the indicators must be turned until zero or naught is visible; and the cylinders must be turned so that the zero on the extreme left i.e., nearest to the indicators is visible.

Let’s see an example

To add the following figures:









Turn the cylinder towards you till 4 appears in the first column at the left end—stop, start again from the Zero or Red Square, now visible till you come to 5 in that column; start again from the Zero or Red Square, now visible, till yon come to 7 in that column; start again from the Zero or Red Square, now visible, till you come to 3 in that column; start again from, the Zero or Red Square, now visible, till you come to 4 in that column.

On looking at the indicator you will find figure 2 recorded, and figure 3 will be the figure now visible at the left end of the cylinder, the two together making 23 which is the required total.

Note: The result of any addition will always be found by reading the figures recorded on the indicators together with the first figure on the left end of the cylinders.

old house
Leonard and Jane Stowe lived in a nice wooden house called Te Moana (later known as Tiakiwai) at 2 Tinakori Road, Wellington.

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