Diffraction Grating

Rutherfurd, Lewis Morris · 1877

Charles A. Young, professor of astronomy at the College of New Jersey (later Princeton University), acquired this diffraction grating in 1877. The speculum metal plate measures 3 inches square, with the grating measuring 1.75 inch square. It is marked "Dec. 1, 1877" and "14,941 lines" and "8640 per inch" and "Manf. by D. C. Chapman with Mr. Rutherfurd's Engine. No. 175, 2 Ave. N. Y." Daniel C. Chapman was the mechanic who operated the ruling engine designed and built by Lewis M. Rutherfurd.