Goldschmidt goniometer
Date1909-1920
Inventory Number2004-1-0338
ClassificationGoniometer
Subject
Maker
Stoe & Cie
1887-present
Maker
Bausch & Lomb Optical Company
1853-present
Maker
Standard Transformer Corporation
1930s-present
Cultural Region
Place of Origin
Dimensions56 x 92 x 53 cm (22 1/16 x 36 1/4 x 20 7/8 in.)
including table: 141 x 122 x 64 cm (55 1/2 x 48 1/16 x 25 3/16 in.)
including table: 141 x 122 x 64 cm (55 1/2 x 48 1/16 x 25 3/16 in.)
Material
Accessoriestable-mounted; embedded, modern electric lights
DescriptionA large metallic instrument on a wooden base which in turn rests on a table with wooden top and iron legs. The instrument consists of two almost-separate pieces: the goniometer proper, and the collimated light source which stands partially on a wooden cube and whose end is supported by an arm of the goniometer. In addition, the base holds a transformer that is the power source for the collimator and for two other lights that are part of the goniometer.
The goniometer is composed of an iron base with three legs (one of which continues upward to hold an end of the collimator) that holds an axis on which two concentric horizontal wheels are mounted. The larger wheel is fixed and holds the movable base of a brass telescope that uses it as a rail. The smaller brass wheel supports a horizontal bar that holds another wheel assemblage, this time with a vertical wheel. On the other side of the horizontal bar is a counterweight. The steel and brass vertical wheel assemblage supports a complex holder at its end.
Both the horizontal brass wheel and the vertical wheel have a set of eyepiece and (electric) light to determine the angle to which they are rotated very accurately.
The collimated light source is composed of a light attached to a telescope-like extension that points towards the goniometer.
The goniometer is composed of an iron base with three legs (one of which continues upward to hold an end of the collimator) that holds an axis on which two concentric horizontal wheels are mounted. The larger wheel is fixed and holds the movable base of a brass telescope that uses it as a rail. The smaller brass wheel supports a horizontal bar that holds another wheel assemblage, this time with a vertical wheel. On the other side of the horizontal bar is a counterweight. The steel and brass vertical wheel assemblage supports a complex holder at its end.
Both the horizontal brass wheel and the vertical wheel have a set of eyepiece and (electric) light to determine the angle to which they are rotated very accurately.
The collimated light source is composed of a light attached to a telescope-like extension that points towards the goniometer.
Signedon horizontal brass wheel: P. Stoe Inh. Fritz Rheinheimer / Heidelberg, Germany
on transformer: Part. no. P-3022 / Standard Transformer Corp. / Chicago, lIL
on illuminator: Bausch and Lomb
Curatorial RemarksThe goniometer is from around 1909-1920 except for the lights which probably have been replaced several times, the last of them around the 1950s.
Because it is signed with with the name of Fritz Rheinheimer, the nephew of Stoe, we know it was made after 1909.
FunctionThis is an instrument that is used to determine the angles made by adjacent crystal faces, which used to be the primary way to identify crystals up to the 1920s. It can also be used to determine the refractive index of a crystal by measuring the angles that light makes when crossing through it.
The goniometer is an assemblage that works by being able to hold and rotate a small crystal by any angle, and accurately measure these rotations. The crystal would be affixed (usually by wax) to the holder at the end of the vertical wheel system with the most prominent straight edge of the crystal pointing vertically. One would point the collimated light (which produces a narrow strip of light) at an angle of about 45 degrees to one of the faces adjacent to the vertical edge, and also point the telescope towards the same face, also about 45 degrees to it, making a right angle to the collimator such that the light would be reflected by the crystal face and be seen in the telescope as a narrow strip of light. One would write down the angles at which this occurred, and then rotate the horizontal brass wheel until the next crystal face (across the vertical edge) reflected the collimated light in exactly the same way. Writing down these new measurements and subtracting the first ones, one would get the exact angle between the two crystal faces. This process would be continued and one could even use the system to measure the angles of the other (non-vertical) crystal edges by using combinations of movements of the vertical and horizontal wheels and using more complex mathematical formulas to deduce the angles.
The eyepieces and electric lights that are mounted on the system help determine the angles as accurately as possible and were needed as the goniometer was operated in a darkened room. The light may have been originally gas or arc-based.
The goniometer is an assemblage that works by being able to hold and rotate a small crystal by any angle, and accurately measure these rotations. The crystal would be affixed (usually by wax) to the holder at the end of the vertical wheel system with the most prominent straight edge of the crystal pointing vertically. One would point the collimated light (which produces a narrow strip of light) at an angle of about 45 degrees to one of the faces adjacent to the vertical edge, and also point the telescope towards the same face, also about 45 degrees to it, making a right angle to the collimator such that the light would be reflected by the crystal face and be seen in the telescope as a narrow strip of light. One would write down the angles at which this occurred, and then rotate the horizontal brass wheel until the next crystal face (across the vertical edge) reflected the collimated light in exactly the same way. Writing down these new measurements and subtracting the first ones, one would get the exact angle between the two crystal faces. This process would be continued and one could even use the system to measure the angles of the other (non-vertical) crystal edges by using combinations of movements of the vertical and horizontal wheels and using more complex mathematical formulas to deduce the angles.
The eyepieces and electric lights that are mounted on the system help determine the angles as accurately as possible and were needed as the goniometer was operated in a darkened room. The light may have been originally gas or arc-based.
W. Watson & Sons Ltd.
Date: circa 1885
Accessories: oculars (2 pairs): B and D; objectives in marked canisters (4): 1/4, 1/2, 1, 3 inches; condenser with iris diaphragm; rotating wheel diaphragm; iris diaphragm; set of 4 disk diaphragms in brass box; triple nosepiece; live box; prisms for Wenham binocular system (2); stage for simple microscope with rotating wheel diaphragm; vulcanite stage; spare knobs (2); parts box; case
Object number: 1249
Martin J. Buerger
Date: 1945-1960
Object number: 1998-1-1673a
Buff & Buff Manufacturing Company
Date: circa 1905
Accessories: wood case; leather case; right-angle prism; plumb bob; oil flask; tripod (5174b)
Object number: 5174a
Carl Zeiss Jena
Date: circa 1926
Accessories: wooden box with two hook-and-eye latches to fasten front opening; in instrument file: instruction book (photocopy); Geissler tube labeled "H2"; carboard tube containing German thermometer C in stainless steel holder that screws into instrument; glass bottle with cork stopper labeled "Monobromnaphthalin, Germany nD=1 658"; small round cardboard box labeled "For Pulfrich Refractometer" containing one tubulure
Object number: 1996-1-0229
Johann August Oertling
Date: circa 1860
Accessories: box of crystal holders (2007b)
Object number: 2007a
Johann August Oertling
Date: circa 1860
Object number: 2002
Martin J. Buerger
Date: 1941-1944
Accessories: film holder (a); metal screen (b); small rectangular metal counterweight (c)
Object number: 1996-1-0185
Rudolf Fuess
Date: circa 1900
Accessories: wooden case; xeroxed article from Crystallography, N. Story-Maskelyne, Oxford 1898, p. 394-399, [The morphology of crystals] (describes in detail the use of the instrument); Stereo photograph of some experimental arrangement, perhaps a spectrometer; Spectrum photograph of Fluorit, signed "Victor Schumann, Leipzig 1901"
Object number: 1997-1-1752
Rudolf Fuess
Date: circa 1900
Object number: 1997-1-1731
Jakob Amsler
Date: circa 1906
Accessories: instrument is in four (4) parts; the rail is in own box and is inventory # 2006-1-0002b; letter from Prof. William Brower containing the complete history of ownership and use (missing)
Object number: 2006-1-0002a