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  • Print publication year: 2014
  • Online publication date: April 2014

2 - The analysis of sunlight: the earliest pioneers


Isaac newton and the composition of sun light

The story of solar, and hence also of astronomical spectroscopy, began in 1666 when the young Isaac Newton (1642–1726) wrote these famous words:

I procured me a Triangular glass-Prisme, to try therewith the celebrated Phaenomena of Colours. And in order having darkened my chamber, and made a small hole in my window-shuts, to let in a convenient quantity of the Suns light, I placed my Prisme at his entrance, that it might thereby be refracted to the opposite wall. [1]

The quotation is from Newton's first paper, which he sent in 1672 to the Royal Society. As he himself notes, the phenomenon was already well known and views on the nature of colour by Descartes, Grimaldi, Hooke and others had already been published. The key feature distinguishing Newton's repeat of the experiment was probably his large distance from the prism to the screen or far wall [2]. Newton tells us he used a wall 22 feet from the prism, so allowing sufficient space for the colours to separate out and to give a clear spectrum. ‘Comparing the length of this coloured spectrum with its breadth, I found it about five times greater; a disproportion so extravagant, that it excited me to a more than ordinary curiosity of examining, from whence it might proceed’ [1].

[1] Newton, I., Philos. Trans. R. Soc., 6 (no. 80), 3075 (1672).
[2] Kuhn, T. S., Newton's Optical Papers, Published in Isaac Newton's Papers and Letters on Natural Philosophy, edited by I. E., Cohen. Cambridge, MA: Harvard Univ. Press (1958).
[3] Newton, I., Opticks 1st ed. 1704; 4th ed. 1730. Republished by Dover Books (1952).
[4] Newton, I., in Letter to Henry Oldenburg, secretary of the Royal Society, dated 13 April 1672. See also Newton's Lectiones Opticae, written 1669—70, published London (1729).
[5] Kayser, H., Handbuch der Spectroscopie, Vol. I, p. 4 Leipzig: Hirzel-Verlag, (1900).
[6] Herschel, F. W., Philos. Trans. R. Soc., 90, 255 (1800).
[7] Herschel, F. W., Philos. Trans. R. Soc., 90, 284 (1800).
[8] Herschel, F. W., Philos. Trans. R. Soc., 90, 293 and 437 (1800).
[9] Biot, J. B., L'Institut (1813) and Gilberts Ann. der Phys., 16, 376(1814).
[10] Ritter, J. W., Gilberts Ann. der Phys., 7, 527 (1801) and ibid., 12, 409 (1803).
[11] Young, T., Philos. Trans. R. Soc., 92, 12 (1802).
[12] Wollaston, W. H., Philos. Trans. R. Soc., 92, 365 (1802).
[13] Brewster, D., Rep. British Assoc., p. 308 (1832).
[14] Chance, W. H. S., Proc. Phys. Soc., 49, 433 (1937).
[15] Seitz, A., J. Fraunhofer und sein optisches Institut. Berlin: Springer-Verlag, (1926).
[16] Fraunhofer, J., First as lectures to the Munich Academy of Sciences in 1814 and 1815, printed in: Denkschriftender Münch. Akademie der Wissenschaften, 5, 193 (1817) and also in: Gilberts Ann.der Phys., 56, 264 (1817). His work was published in English in: Edinburgh Philos. J., 9, 296 (1823) and ibid 10, 26 (1824).
[17] Fraunhofer, J., Denkschriften der Münch. Akademie der Wissenschaften, 8, 1 (1821).
[18] Fraunhofer, J., Gilberts Ann. der Phys., 74, 337 (1823).