Carangeot-type contact goniometer
Date: circa 1797
Inventory Number: 1999-1-0034
Classification: Goniometer
Subject:
Maker: W. & S. Jones (fl. 1791 - 1859)
User: Benjamin Waterhouse (1754 - 1846)
Cultural Region:
Place of Origin:
City of Use:
Dimensions:
goniometer: 2.1 × 10.9 × 4.9 cm (13/16 × 4 5/16 × 1 15/16 in.)
case: 2.3 × 12 × 6 cm (7/8 × 4 3/4 × 2 3/8 in.)
Accessories: original case
Description:
This Carangeot-type goniometer consists of a graduated semicircular arc whose diameter also serves as the stationary measuring limb; the left end of the diameter is not connected to the arc. The second limb rotates around the center of the circle. Both limbs are equipped with internal slots, so that the pointed ends can be appropriately shortened or lengthened through parallel sliding. A hinge at the center of the arc increases the versatility of the device, while an extra radial arm mounted behind the 40° mark gives it greater stability. Also, typical contact goniometers have the origin of the scale on the right side (to ease measurements), while for this instrument the 0 is on the left (see also 2017).
The goniometer is preserved in its original leather-covered (now partly peeled), brown velvet-lined wood case (cover missing).
The goniometer is preserved in its original leather-covered (now partly peeled), brown velvet-lined wood case (cover missing).
Signedunsigned
FunctionThe purpose of crystallographic goniometry is to measure the interfacial angles of crystals to determine their type.
To determine the angle between two surfaces, one has to hold the crystal edge at the scissor opening between the limbs of the goniometer. The angle being measured is read from the scale. Such contact goniometers usually have an accuracy between 15 minutes and 1 degree.
To determine the angle between two surfaces, one has to hold the crystal edge at the scissor opening between the limbs of the goniometer. The angle being measured is read from the scale. Such contact goniometers usually have an accuracy between 15 minutes and 1 degree.
Historical AttributesPurchased in London in 1797 for Professor Waterhouse (see College Papers IV, 3, 1979 in Harvard University Archives). Possibly the first goniometer in the United States.
The instrument was used by Waterhouse for classroom instruction in mineralogy, then given in the Medical School. (see Clifford Frondel, "An Overview of Crystallography in North America" in McLachlan, Dan and Jenny P. Glusker eds. Crystallography in North America (American Crystallographic Association: New York, 1983), p. 1). The instrument cost 14s and was bought from W&S. Jones (see I.B. Cohen, Some Early Tools of American Science (Harvard University Press: Cambridge, 1950), p. 119-20).
The instrument was used by Waterhouse for classroom instruction in mineralogy, then given in the Medical School. (see Clifford Frondel, "An Overview of Crystallography in North America" in McLachlan, Dan and Jenny P. Glusker eds. Crystallography in North America (American Crystallographic Association: New York, 1983), p. 1). The instrument cost 14s and was bought from W&S. Jones (see I.B. Cohen, Some Early Tools of American Science (Harvard University Press: Cambridge, 1950), p. 119-20).
Curatorial RemarksThis instrument had been given the same inventory number as a full-circle contact goniometer (inv. 2011). Its inventory number was therefore changed to 1999-1-0034, and this new entry made.
Primary SourcesCollege Papers IV, 3, 1979 in Harvard University Archives (See Historical Attributions).
ProvenanceProfessor Frondel, Geology Department, Harvard University
