collimator for Gibbs spectroscope

Date1878

Inventory Number1997-1-0029a

ClassificationSpectroscope

Subject

Maker Alvan Clark and Sons 1846 - 1958

User Oliver Wolcott Gibbs 1822 - 1908

User Department of Chemistry, Harvard University founded 1791

Cultural Region

Place of Origin

Dimensions8.9 × 41.3 × 15.3 cm (3 1/2 × 16 1/4 × 6 in.)

Material

Accessoriesdust cap; mount

DescriptionOptical tube attached to a mount made of an arm and two brackets. A thumb screw under the arm is used to fix it on a support or stand. The telescope has a dust cap protecting the objective lens. The lens has an aperture of 1 7/8 inches (4.7 cm)

The eyepiece end of the telescope has an adjustable slit. There is a focusing knob on the tube.

Signedunsigned

ProvenanceOliver Wolcott Gibbs, Department of Chemistry, Harvard University, 1878.

Historical AttributesThis spectroscope is likely the one made by Alvan Clark & Sons for Oliver Wolcott Gibbs in 1878. Gibbs was the Rumford Professor at Harvard, and the Smithsonian Institution Annual Report of 1878 mentions a spectroscope made by the firm in 1878 for the Rumford Cabinet at Harvard. The collimator for the spectroscope had an objective lens of 6.5 cm in aperture and 1.6 meters focus. The Clarks made a number of spectroscopes on this design for astronomical and chemical use. An engraving of a similar instrument made in 1877 for use with Princeton's 9-inch Clark refractor is depicted in Charles A. Young's The Sun (New York, 1896), 69 and reprinted in Artists in Optics (see references). Gibbs used spectroscopy in his chemical research, and invented a new form of spectroscope in 1862. According to a letter he wrote to Benjamin Silliman, published in 1863, it was made by J. & W. Grunow of Boston and used a special prism with a refracting angle of 37°. The article continues: "Under these circumstances the refraction takes place at an angle so near the limiting angle that the refracted rays emerge nearly parallel to the second surface of the prism. The amount of dispersion produced in this manner is very great, while the loss of light, occasioned by reflection at the first surface in prisms of 60° placed in the position of least deviation, is avoided. The spectrum thus produced possesses remarkable intensity and the dark lines are seen in countless numbers and with great distinctness." For more details, see <a href="http://books.google.com/books?id=cWkWAAAAYAAJ&pg=PA110&lpg=PA110&dq=%22gibbs+spectroscope%22&source=bl&ots=EsbT4EhPTc&sig=fHzKb-uVheu1h_dNldEdiyk3vdc&hl=en&sa=X&oi=book_result&resnum=5&ct=result" target="_blank">Google Books</a>. This spectroscope (CHSI inv. 1997-1-0029a-d) is not that same instrument, but is much larger.