During the period 1900-1903, Ernest Fox Nichols and Gordon Ferrie Hull carried out the first precise measurement of the radiation pressure of light
on a macroscopic body in the Wilder Physical Laboratory, Dartmouth College. James Clerk Maxwell had predicted this effect in 1873 based upon
calculated stresses in the electromagnetic field. It was also predicted by Adolpho Bartoli in 1876 based on a thermodynamics argument. All earlier
attempts to experimentally observe this effect had been thwarted due to the disturbing action of the residual gases surrounding the body upon which
the radiation fell, even in the best vacuums achievable at the time. The radiation pressure was predicted to be the energy density in the light beam,
independent of the wavelength. The experiments of Nichols and Hull succeeded, where others had failed, by making a detailed empirical analysis of the
ubiquitous gas heating and ballistic effects. The published papers [Nichols, E. F., and Hull, G. F., A preliminary communication on the pressure of
heat and light radiation, Phys. Rev. 13, 307 (1901); The Pressure Due to Radiation. (Second Paper.), Phys. Rev. 17, 26 (1903)] reveal the incredible
experimental acumen of Nichols and Hull. The final results agreed with Maxwell's theory to better than one percent. The tiny force involved in their
torsion balance radiometer was of order 10-4 dyne. (Remember that a dyne is approximately the weight of a postage stamp.) A considerably less
accurate demonstration (about 20 percent) was carried out independently at around the same time by Pyotr Lebedev at Moscow State University in Russia
[Lebedev, P., Untersuchungen uber die Druckkrafte des Lichtes, Ann. Phys. (Leipzig) 6, 433 (1901)]. So convincing were the results of Nichols and
Hull that, as far as we know, no subsequent physicists sought to repeat their experiments. By 1910, review articles and textbooks, especially
astronomy texts discussing the pressure of light as the force bending comets' tails, routinely referred to Maxwell's prediction and to Nichols' and
Hull's experimental confirmation of light pressure [see Lewis, G., A revision of the fundamental laws of matter and energy, Phil. Mag. 6th ser., 16,
706 (1908); Page, L., A century's progress in physics, Am. J. of Sci, 4th ser., 46, 316-17 (1918); Russell, Dugan, and Stewart, Astronomy (1927),
478].
These experiments came at the time of the revolutions in physics having to do with relativity and quantum mechanics, and were perhaps overshadowed by these events.
