Usage/History: The oldest optical method for chemical
analysis, Bunsen and Kirchhoff introduced spectroscopy as a laboratory
method in 1860. The basic features of the spectroscope (or spectrometer)
include a slit and collimator to produce a parallel beam of light
which then falls on the dispersive element (a prism or grating).
The resulting spectrum is then observed through a telescope.
Spectrometers are particularly valued in two types of studies:
1) The identitfication and quantification of elements by the
observation of line spectra (emission or absorption), 2) The
identification and quantification of substances by the observation
of absorption bands.
In this spectrometer the prism table, the collimator, and
the telescope positions may be determined relative to a graduated
circle. This example is AO Spencer's student instrument. It could
be used for the determination and analysis of spectra using either
a prism or grating. It could also be used in the measurement
of angles between prism faces, the determination of angles of
refraction and reflection etc. In another common type of instrument,
the Bunsen
Spectroscope, there is no graduated circle, instead measurements
are made relative to a projected scale.
Some contemporary/early descriptions of the spectroscope
and its use are provided below:
"The
Spectrometer" in Minor. Physical Measurements:
... Sound and Light (1917)
Bennet, J. A. The Celebrated Phaenomena of Colours: the
early history of the spectroscope. Whipple Museum of the
History of Science, Cambridge (1984).
Brand, John C. D. Lines of Light: The Sources of Dispersive
Spectroscopy, 1800-1930. Gordon and Breach Publishers (1995)
Minor, Ralph S., Physical Measurements, A Laboratory Manual
in General Physics for Colleges: Part 2, Magnetism and Electricity,
Sound and Light 3rd ed, Associated Student's Store, Berkeley
(1956) pp. 118-121, 122-124, 158-159.
