Early diffraction experiments
Stories from Physics for 11-14 14-16
One of the earliest reports of diffraction used a feather as a grating. In a 1673 letter, James Gregory wrote to John Collins who acted as ‘post office’ to disseminate information in the scientific community:
“If ye think fit, ye may signify to Mr Newton a small experiment, which (if he know it not already) may be worthy of his consideration. Let in the Sun’s light by a small hole to a darkened house, and at the hole place a feather, (the more delicate and white the better for this purpose) and it shall direct to a white wall or paper opposite to it a number of small circles and ovals, (if I mistake them not) whereof one is somewhat white, (to wit, the middle, which is opposite to the Sun) and all the rest severally coloured. I would gladly hear his thoughts of it.”
S. Rigaud (ed.), Correspondence of Scientific Men of the Seventeenth Century, Letters of Barrow, Flamsteed, Wallis, And Newton, From the Originals in the Collection of the Right Honourable Earl of Macclesfield, Volume II, Oxford, Oxford University Press, 1841, p. 254.
T. D. Cope, The Rittenhouse diffraction grating. Journal of the Franklin Institute, vol. 214, no. 1, 1932, pp. 99-104, p. 99.