This slide rule is from the collection of calculating instruments assembled by Assoc. Professor Allan Bromley. His collection provides examples of most forms of calculating devices made from the early 18th to the late 20th centuries. The slide rule forms a substantial proportion of this collection.

Over the 19th and much of the 20th centuries the slide rule was the primary instrument for calculation used by many people engaged in the trades and in engineering. Although originally invented in the 17th century, and widely used for gauging (or estimating the quantities of certain products such as alcoholic spirits) it took until around 1850 for the slide rule to become generally popular.

One area in which slide rules have been used since their inception is in range finding for use with artillery. This example is a Japanese slide rule probably for artillery use. It also has map-reading scales. Damian Allen suggests it was made in the 1920's +/- 10 years, making it a product of the Meiji or the Taisho eras of Japanese culture, and that it may have been used with Type 31 or Type 38 (c 1905) field guns.

Bromley purchased: Maitland, Portobello Rd - 14/12/85 - Lstg110

Slide rule, navigation or gun laying, closed frame, single-sided, double-sided slide, brass / glass, maker unknown, Japan, 1920s

Slide rule, Japanese navigation or gun laying, closed frame, single-sided, double-sided slide, solid brass with brass rimmed glass cursor. With 28cm rule on top bevelled edge and 5:1 scale mm rule on squared bottom edge. In leather holster case with felt lining.

Scale markings in simplified Kanji, no maker's marks.
Scales:
Stock, upper: log scale 1 - 10,000
Slide, obverse: log scale 1 - 10,000, map scale conversions: 1/16, 1/6400
Slide, reverse: split log scale 1 - 1600 and 1600 - 3199
Stock, lower: log scale 1 - 10,000

Bromley note:
Apparently navigation or gunnery rule, reportedly c.1870 but possibly c.1900-WWI.

Damian Allen suggests:
Possible artillery use noting 1/6400 (mils) scale. [The] cm scale [indicates] use on map [for] cartographic survey. Possibly] 1920's Japanese +/- 10 years Meiji or Taisho.

Made: 1920 - 1929

scales with Kanji labels

2010/1/566

1920 - 1929