Woltmann Water Current Meter

In 1847, a French hydraulic engineer named André G. A. Baumgarten published an account of his work with a horizontal-axis current meter that was based on the form described by Reinhard Woltmann, a German hydraulic engineer, in 1790. Lerebours et Secretan (fl. 1845-1855), a prominent instrument firm in Paris, began offering a “Moulinet de Woltmann” soon thereafter, noting that this form was used in the hydraulic service of the Ponts et Chausées, the national agency in charge of bridges and roads.
The “Lerebours et Secretan / à Paris” signature on this example dates from the period 1845-1855. The instrument came from the Proprietors of the Locks and Canals, the corporation that developed water transportation along the Merrimack River, and water power for the town of Lowell, Massachusetts. James B. Francis probably acquired it shortly after having been named manager of that organization. It came to the Smithsonian in 1956, and was restored by the U.S. Geological Survey in 1958.
Clemens Herschel opined in 1869 that “The best instrument to measure the velocity of the current at any point has generally been thought to be the so-called Woltmann wheel, or tachometer.” James B. Francis did not mention an instrument of this sort in the first (1855) edition of his Lowell Hydraulic Experiments, but in 1868 he noted that “Woltman’s mill, or tachometer, has been much used for this purpose, but to insure correct results, its application is one of much delicacy, and in our large channels would require much time.”
Ref: A. G. A. Baumgarten, “Sur le moulinet de Woltmann destiné à mesurer les vitesses de l’eau, sur son perfectionment et sur les experiences avec cet instrument,” Annales des Ponts et Chausées, Memoires et Documents (1847): 326-357.
Lerebours et Secretan, Catalogue et Prix des Instruments (Paris, 1853), p. 138.
James B. Francis, (New York, 1868), p. 156.
Clemens Herschel, “Gauging the Flow of Rivers, &c.,” Journal of the Franklin Institute 87 (1869): 305-315.
Arthur H. Frazier, Water Current Meters in the Smithsonian Collections of the National Museum of History and Technology (Washington, D.C., 1974), pp. 49-50 and 56-57.
Paolo Brenni, “Lerebours et Secretan,” Bulletin of the Scientific Instrument Society 40 (1994): 3-6.
Currently not on view
date made
Lerebours et Secretan
place made
France: Île-de-France, Ville de Paris, Département de
overall: 17 1/2 in; 44.45 cm
overall: 6 3/4 in x 18 in x 2 1/8 in; 17.145 cm x 45.72 cm x 5.3975 cm
ID Number
accession number
catalog number
Credit Line
Proprietors of the Locks and Canals
See more items in
Medicine and Science: Physical Sciences
Measuring & Mapping
Water Currents
Data Source
National Museum of American History, Kenneth E. Behring Center


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