Retcofsky’s letter contains the assertion that Alter was the first to describe the Balmer lines of hydrogen in 1855. Perhaps this statement was inferred from a similar remark in Hodge’s biographical paper (2). However, there is no doubt (3, 4) that the Balmer lines were already discovered by Ångström in 1853 (5).

To complement what has been said in ref 1 about Alter’s work on the spectral lines of brass, it might furthermore be pointed out that Ångström in ref 5 also dealt with the observation that the spectrum of an alloy of two metals contains the spectrum of each of the constituents (6).

Literature Cited

1. Retcofsky, H. L. J. Chem. Educ. 2003, 80, 1003.
2. Hodge, E. S. Appl. Optics 1976, 15, 1722–1725.
3. Schawlow, A. L. Rev. Mod. Phys. 1982, 54, 697–707.
4. Pais, A. Inward Bound; Oxford University Press: New York, 1986; p 166.
5. Ångström, A. J. Kongl. Svensk. Vetenskapsakad. Handlingar 1852, 333–360. (Translations: Phil. Mag. 1855, 9, 327–342; Ann. Phys. 1855, 94, 141–165.)
6. Maier, C. L. in Dictionary of Scientific Biography, Vol. I; Scribner’s Sons: New York, 1970; pp 166–167.

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