This spectroscope was designed to be used with a telescope to study the light of the sun. It was made in Dublin in 1877 by the famous instrument maker Howard Grubb (1844–1931). It was used with the 9 ½ inch Alvan Clark & Sons refractor at Princeton University.
When the College of New Jersey at Princeton hired the astronomer Charles A. Young in 1877, they also gave him funds to equip the new John C. Green student observatory. One of his first purchases was this instrument. It was custom-made, and Young helped refine the design. (Grubb's company later advertised that this was the first such spectroscope that they had sold.) The most unusual feature of this instrument is the use of a complicated system of multiple prisms to disperse the light and produce a highly detailed view of the solar spectrum.
In use, the spectroscope was mounted at the eyepiece end of the telescope and light from the sun would be directed through it. As the light passed from one prism into the next, it would be increasing dispersed, or spread out. To make the instrument more compact, the beam of light was directed first through the upper portion of the prisms and then back through the bottom part. Depending on how it was configured, the light could thus be passed through either 2, 4, 6 or 8 prisms. A particular area of the solar spectrum could be viewed by turning a small chain that moved each prism by the same amount. Because of the large number of optical surfaces involved, the light loss in this instrument was almost certainly in the 90 percent range. This was an advantage when viewing the Sun, but it reduced the usefulness of this instrument for other purposes, such as measuring the spectra of stars. The success of this instrument in making precise measurements of the solar spectrum (and thus revealing information about the composition of the sun and its atmosphere) led to its wider adoption as an important astronomical tool.
Ever since the invention of the telescope around 1600, many opticians have considered the advantages of binocular telescopes, and some actually produced instruments of this sort. The form, however, did not become widely available until the latter decades of the19th century. This example is an aluminum instrument with aluminum sunshades. The objective lenses are about 1.6 inches diameter; the length overall, when closed, is about 11 inches. One eyepiece barrel is marked “T. W. Watson / Optician” and the other is marked “4 Pall Mall / London.” The cross frame has two knobs, one for focusing and one for adjusting the inter-ocular distance. The barrels are covered with black leather. The case is brown leather.
T. W. Watson (fl. 1868 to 1884) sold guns and optical instruments.
Brass instrument with a black japan finish. The objective lenses are about 40 mm diameter, and the optics are excellent. The “CHEVALIER * PARIS” inscription on each eyepiece refers to an optical firm that was begun by Louis Vincent Chevalier in 1765, and that was still in the business in the late 19th century. The left eye tube is marked “DAY & NIGHT / EXTRA POWER” and the right is marked “ARMY & NAVY / EXTRA POWER.” The case is black leather.
Ref: Paolo Brenni, “19th Century French Scientific Instrument Makers. II: The Chevalier Dynasty,” Bulletin of the Scientific Instrument Society 39 (1993): 11–14.
Aluminum binoculars with a black finish, and black leather on the barrels. The left eye plate is marked “CARL ZEISS / JENA” and the right on is marked “DELACTIS / 1135801 / 8 x 40.” The objective lenses are 40 mm diameter. The eyepieces are separately adjustable as is the inter-ocular distance. The case is black leather.
Zeiss produced the Delactis form between 1921 and 1936.
Each eyecup of this small instrument is marked “LEMAIRE FABT * PARIS .” The objective lenses are 30 mm diameter and the optics are good. The frame is a gilt metal. The barrels, eyecups and center focusing wheel are covered with mother of pearl. An image of a bee, the Lemaire logo, appears on the central brace; if there was once a number there, it is not now visible. The red leather carrying case is probably not original.
Jacques Lemaire began making opera glasses in 1847 and was soon a major manufacturer noted for using mechanization, division of labor and interchangeable parts. M.J.B. Baille joined the firm in 1871, and took charge in 1885.
Ref: Nicholas Gilman, A Dividend to Labor: A Study of Employers’ Welfare Institutions (Boston and New York, 1899), pp. 297–304.
When closed, this ingenious device appears as a simple tube covered with dark leather. When opened it is a binocular instrument. The “BTE SGDG” inscription on the focusing knob indicates that it is based on a French patent. The objective lenses are 29 mm diameter. The frame is nickel plated.
John Browning in London described an instrument of this sort as a “Portable Binocular.” McAllister in Philadelphia described it as an “Articulated Pocket Opera Glass.”
Ref: John Browning ad in Nature 20 (May 1, 1879): title page.
William Y. McAllister, Illustrated Catalogue of Spectacles, Opera Glasses, Opthalmoscopes and Meteorological Instruments (Philadelphia, 1882), p. 49.
This is a gold-plated brass instrument with a tortoise-shell handle. The barrels are covered with black lacquer. The eyecups are flat and marked “WALDSTEIN ET SOHN MÜNCHEN.” The objective lenses are 23 mm diameter. The three crossbars are fixed. Focus is by rotating the left barrel. The pouch is blue velvet.
This is a metal instrument covered with black leather that probably dates from the World War I period. The eye end of the left prism housing is marked “EXTRA / LUMINEUSE / 8X” and that on the right is marked “HUET /PARIS.” The objective end of one prism housing is marked “M.G. / A. G. 1813.” There is a center focus, and fine adjustment on each eyepiece. In the right eyepiece is a linear scale (a reticle) that runs from -45 to +45, that is graduated in single units, and that could be used to estimate the distance to distant objects.
Huet was an optical firm that began in business in 1892, and that made instruments for the French military during World War I.
A heliostat throws sunlight where it might be needed, whether for photography or scientific observations. This example resembles the Foucault heliostat made by the Société Genevoise. A tag on the base reads: “PRESENTED TO COLUMBIA UNIVERSITY BY ERNEST KEMPTON ADAMS.” Ernest Kempton Adams was a graduate of Columbia University. Following his untimely death in 1904, his large collection of scientific and engineering instruments was given to Columbia, and his father provided $50,000 to support physical research.
Ref: Société Genevoise, Illustrated Price List of Physical and Mechanical Instruments (Geneva, 1900), pp. 85-86.
One eyepiece barrel is marked “Docteur / Arthur Chevalier” and the other “Paris / 158 Palais Royal.” The objective lenses are 30 mm diameter. The frame is black metal. The barrels are covered with black leather. A center wheel adjusts the focus.
Arthur Chevalier (1830-1874) began in business around 1860, taking charge of the optical firm begun by his grandfather, Charles Chevalier, and continued by his father, Louis Vincent Chevalier. M. Avizard bought the firm in 1881.
Ref: Arthur Chevalier, Catalogue Explicatif et Illustré des Instruments d’Optique et de Météorologie (Paris, 1860), pp. 16-20.
Paolo Brenni, “19th Century French Scientific Instrument Makers. II: The Chevalier Dynasty,” Bulletin of the Scientific Instrument Society 39 (1993): 11–14.
This is a black metal instrument with black leather covering the barrels. The objective lenses are 50 mm diameter. The eyepieces focus separately. The eye end of the left prism housing is marked “7 x 50 / MARSEPT” and the right one is marked “E. LEITZ / WETZLAR / 476092.” There is a black leather case.
Leitz made this model between 1932 and 1962. This example may have been used during World War II.
This is a German military instrument marked “Dienstglas N°131375” and “J.R. 82” and “4. K.” The top of the central focus screw is marked “Fernglas Emil Busch A.G. Rathenow 80.” There is a fine adjustment at each eyepiece. The objective lenses are 45 mm diameter.
Emil Busch (1820-1888), took charge of his family’s optical firm in Rathenow in 1845, and renamed it Emil Busch A.G. in 1872. It became Emil Busch A.G. Optische Industrie in 1908.
This a black metal instrument with black leather covering the barrels. The eye end of the left prism housing is marked “RODENSTOCK / IVXA (?)” and the right has text in Arabic, with star and crescent symbol. The translation of the text reads: "the Turkish Republic....made with special lining". The instrument is dated 1927. There is a center focus, and fine adjustment at the eyepieces.
The Rodenstock optical firm began in Würzburg in 1877, and later established offices and factories in Regen and in Munich. It is still in business, and run by descendants of the founders.
Each eyecup of this instrument is marked “BARDOU & SON * PARIS.” The objective lenses are 40 mm diameter. The frame is brass. The barrels are brass covered with black leather. A center wheel adjusts the focus. The carrying case is black leather with a red silk lining.
The Bardou firm was established in 1818, and trading as Bardou & Son by 1876.
This is a brass instrument with center focus, and center adjustment for inter-ocular distance. The objective lenses are 40 mm diameter. The length is 29 cm (closed). Each eye tube is marked “LEVY, DREYFUS & CO / NEW YORK.” These came to the Smithsonian in 1907. A note in the file reads: “Prussian Army Field Glass used in 1885 by the [U.S.] Geological Survey but now discarded because of the small field of view.
Levy, Dreyfus & Co. was in business in New York City in the 1890s, advertising as opticians and wholesale importers.
Most of the field glasses (aka binoculars) used by Americans in the 19th century were imported from Europe. European dominance of the field increased still further in 1893 when Zeiss introduced a prismatic binocular designed by Ernest Abbe. Worcester Reed Warner (of Warner & Swasey) spent $40 for a pair of Zeiss binoculars in 1895, recognized the many advantages of the design, and determined to manufacture similar instruments in the U.S. Warner & Swasey introduced their Universal Prism Field Glass in 1900, boasting that it was "characteristically American in its design and construction, embodying simplicity, compactness, lightness of weight, and elegance of form an finish, together with large field, clearness of definition, ease of manipulation, and freedom from strain to the eyes."
These prism binoculars were probably used during World War I. One inscription reads "Warner & Swasey." Another reads "U.S. NAVY 04350."
The words “12 Verres” on the crosspiece probably indicate that this instrument was made in France. They also indicate that each eye lens and each objective lens is a triple achromat, a design that was developed by Joseph Petzval, a professor of mathematics at the University of Vienna, and introduced to practice by Voightländer & Sohn in the early 1840s. Because of this design, the optics are exceedingly good. The objectives lenses are 44 mm diameter. The frame is gilt metal. The barrels and eyecups are covered with mother of pearl, as is the center wheel that adjusts the focus. The case is dark leather lined with magenta silk.
Ref: Charles Chevalier, Catalogue Explicatif et Illustré des Instruments d’Optique et de Météorologie (Paris, 1860), p. 17.