ClipArt ETC
"...a tube with a slit at the further end through which the light enters, and at the other end a collimating lens which brings the rays into a parallel beam (the slit is formed between two parallel edges the distance between which can be varied at will)..." —Whitney, 1889

Prism Spectroscope from the Late 19th Century

"...a tube with a slit at the further end through which the light enters, and at the other end a collimating…

"The light to be studied is admitted through a narrow slit (A) in the end of a tube, in such a way that it will fall in parallel rays on a prism (C) with its edges parallel to the slit. When the beam emerges from the prism, the different colors are separated and the spectrum is viewed through lenses (E) placed at the end of another tube." -Brownlee 1907

Diagrammatic Representation of Spectroscope

"The light to be studied is admitted through a narrow slit (A) in the end of a tube, in such a way that…

"A spectroscope is an instrument used ot produce a spectrum of the light form any source, and for its study." -Avery 1895

Spectroscope

"A spectroscope is an instrument used ot produce a spectrum of the light form any source, and for its…

"...an instrument which gives a spectrum when the source of the light is in a straight line with the eye—that is, which gives dispersion without deviation—is called a direct vision spectroscope..." —Whitney, 1889

Direct Vision Spectroscope

"...an instrument which gives a spectrum when the source of the light is in a straight line with the…