Fuller's Spiral Slide Rule [Calculator] – Manufacturer W.F. Stanley, London

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Fuller’s Spiral Slide Rule [Calculator] – Manufacturer W.F. Stanley, London

Short Description

Invented by George Fuller, Professor of Engineering at Queens’s College Belfast, patented in 1878.

The rule consists of a logarithmic scale of numbers spiral wound in the form of a helix; the scale is 500 inches [circa 42 feet] in length having 7,250 divisions. This rule is therefore equivalent to a straight slide rule twice that length or c 84 feet. If you understand the principle – it’s the [lack of] length of a slide rule that inhibits accuracy. It can be held in one hand while performing calculations or fixed on the removable brass holder if more convenient. The mahogany box is true to the instrument and has felt covered fittings to protect it in transit. The original instruction booklet is still with the instrument.

The manufacturer was W.H. Stanley at one time the biggest instrument maker in the World. Stanley a Fellow of all the right Societies was an architect and had near 100 patents to his name.

This instrument is one of the last manufactured, which probably accounts for its pristine condition. We can date it to 1965 for two reasons. First, all instruments were numbered at the bottom of the B cursor, and this one is serial number 13111 and below that stamped 65 for 1965. Secondly, there is a magnificent paper published by the esteemed Oughtred Society [Look it up] which gives excellent background information on the instrument and provides a graph of the serial numbers and dates of a good sample from No 1 in 1884 to number 13688 in 1973 – so you can see that ours is placed right in the twilight zone.

We find it interesting that only 14,000 instruments were ever made over a period of 90 years. After a slowish start and an end tail-off the graph of units made is pretty steady with a bit of a jolt during WWI and WWII. Your guess is right it was killed pretty dead by Hewlett Packard.

We haven’t gone into full details of how the instrument is constructed and functions, but we do have information in our Research Section, and you can always look up the aforementioned “Oughtred” reference – best information going - forget Wiki.

In terms of size the box is 46 cm x 12 cm x 11 cm. The rule is 43 cm long 9 cm in diameter.. Total weight around 2 kgs.

A postage supplement may be required dependent on location of buyer.

Fullers system of spiral slide rule – top of the pile and an instrument of some beauty

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