An Arithmometer in the Whangārei Museum collection. Photo / Supplied
An Arithmometer in the Whangārei Museum collection. Photo / Supplied
I am comfortable admitting that numbers are not my forte. Even so, I absolutely loved maths at school - I found it fascinating to try and understand the world through mathematics.
I also remember being advised that you couldn't be reliant on gadgets, for example, your calculator.
But on eyeingthese early calculators, I realised that the generations before me also embraced aides. These early calculators are practical machines that help reduce human error.
In the Whangārei Museum collection, we have an Addometer and an Arithmometer. The Original Odhner Arithmometer, made in Sweden, is a pinwheel calculator.
The Whangārei Museum's Arithmometer is likely from the mid-1900s. Photo / Supplied
The first version was made in 1875, though this model is likely from the mid-1900s (1935-1945). This machine is designed for addition, subtraction, multiplication, and division.
Multiplication is repeated addition, and division is repeated subtraction - the machine calculates all these functions by rotating the main handle. The small register on the left shows the results of multiplication and division, and the large register is for addition and subtraction. The two small cranks at the front are for clearing the device.
The Odhner became the most commercially successful, general, mechanical calculator, which is likely why this machine was imported by Armstrong & Springhall Ltd to New Zealand and purchased by the Lands & Survey Department in 1946.
The Addometer, manufactured by the Reliable Typewriter and Adding Machine Corporation in Chicago, is another example of a mechanical calculator. It was first produced in 1927 but production ceased in the mid-1960s.
The Addometer is much lighter than the Arithmometer, weighing just 430 grams. This Addometer is a regular model, without a fractions dial.
Its use is most suited to a shop or home because of its simplicity. The ruler along the top edge would have been handy in either environment. The addometer operates with the use of a stylus.
An Addometer that is part of the Whangārei Museum collection. Photo / Supplied
For addition, you spin the dials clockwise using the larger numbers and to subtract you focus on the small numbers and rotate anti-clockwise - it has an automatic carry-over function that operates in both directions. To clear the device and start afresh, you pull the small protruding lever on the right.
Since the 1970/80s mechanical calculators have been surpassed by electronic versions. The operating process of these mechanical machines is satisfying because you can see how the parts interact with each other - a novel experience having grown up in the digital age. I appreciate the design and function of these calculators, though I am thankful to have my mobile phone for impromptu calculations.
