Revolution Counter by A. Sainte of Paris

This portable revolution counter has a handle at one end. The point at the other end is pressed against the end of the axis of the shaft whose revolutions are counted. In between are two wheels. When the lower wheel turns once, the upper wheel moves one tenth of its circumference. The edges of both wheels are divided into 100 equal parts. Each tenth division is numbered.
The lower wheel is labeled: TENS. Its divisions are numbered clockwise from 0 to 9 on the inside, and counterclockwise from 0 to 9 on the outside. The upper wheel is labeled: HUNDREDS. Its divisions are numbered counterclockwise from 0 to 9 on the inside and clockwise from 0 to 9 on the outside. A spring disengages the wheels to allow zeroing.
A mark on the back of one wheel reads: A. Sainte (/) A Paris.
The end of the shaft has three attachments. The instrument also has a metal weight and fits into a velvet and satin-lined case.
By counting the number of revolutions of the shaft of a steam engine and knowing the steam pressure and the properties of the engine, steam engineers could compute the horsepower of the engine. A. Sainte patented a device for this purpose in 1877, and exhibited it at the Exhibition Universelle held in Paris in 1878. A form of the device was still being manufactured as late as 1903.
J. Buchetti, Engine Tests and Boiler Efficiencies, trans. Alexander Russell, Westminster: Archibald Constable, 1903, pp. 120-123.
Science Museum, Catalogue of the Mechanical Engineering Collection of the Science Museum South Kensington, London: HIs Majesty’s Stationery Office, 1919, pp. 234-235.
Currently not on view
Object Name
counter, analog
date made
ca 1880
A. Sainte
Physical Description
wood (overall material)
cloth (overall material)
metal (overall material)
overall: 2.7 cm x 14.3 cm x 7.8 cm; 1 1/16 in x 5 5/8 in x 3 1/16 in
place made
France: Île-de-France, Paris
ID Number
accession number
catalog number
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History, Kenneth E. Behring Center


"Missing from the A. A. Sainte information is the important (to future researchers) fact that Sainte obtained a United States patent for this instrument.Date: 1/7/1879Patent number: 211274Title: Rotary Speed IndicatorPatentee: A. A. Sainte, Paris France not assignedThanks much for providing all of the valuable information contained on this site."

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