ferent bodies, independently of their color. Nor should we neglect to emphasize, in this connection, the importance of his measurements of the intensity of the heat and light in the different portions of the solar spectrum. It is the more necessary to state Herschel's claims clearly, as his work has been neglected by those who should first have done him justice. In his "History of Physics," Poggendorff has no reference to Herschel. In the collected works of Verdet, long bibliographical notes are appended to each chapter, with the intention of exhibiting the progress and order of discovery. But all of Herschel's work is overlooked, or indexed under the name of his son. One little reference in the text alone shows that his very name was not unknown. Even in the great work of Helmholtz on physiological optics, Herschel's labors are not taken account of.
It is easy to account for this seemingly strange neglect. Herschel is known to this generation only as an astronomer. A study of his memoirs will show that his physical work alone should give him a very high
