II. Special Periods.
Chapters I. and II.—In addition to the general histories quoted above—especially Wolf—I have made most use of Tannery's Recherches sur l'Histoire de l'Astronomie Ancienne and of several biographical articles (chiefly by De Morgan) in Smith's Dictionary of Classical Biography and Mythology. Ideler's Chronologische Untersuchungen, Hankel's Geschichte der Mathematik im Alterthum und Mittelalter, G. C. Lewis's Astronomy of the Ancients, and Epping & Strassmaier's Astronomisches aus Babylon have also been used to some extent. Unfortunately my attention was only called to Susemihl's Geschichte der Griechischen Litteratur in der Alcxandriner Zeit when most of my book was in proof, and I have consequently been able to make but little use of it.
I have in general made no attempt to consult the original Greek authorities, but I have made some use of translations of Aristarchus, of the Almagest, and of the astronomical writings of Plato and Aristotle.
Chapter III.—The account of Eastern astronomy is based chiefly on Delambre, and on Hankel's Geschichte der Mathematik im Alterthum und Mittelalter; to a less extent on Whewell. For the West I have made more use of Whewell, and have borrowed biographical material for the English writers from the Dictionary of National Biography. I have also consulted a good many of the original astronomical books referred to in the latter part of the chapter.
I know of no accessible book in English to which to refer students except Whewell.
Chapter IV.—For biographical material, for information as to the minor writings, and as to the history of the publication of the De Revolutionibus I have used little but Prowe's elaborate Nicolaus Coppernicus, and the documents printed in it. My account of the De Revolutionibus is taken from the book itself. The portrait is taken from Dandeleau's engraving of a picture in Lalande's possession. I have not been able to discover any portrait which was clearly made during Coppernicus's lifetime, but the close resemblance between several portraits dating from the 17th century and Dandeleau's seems to shew that the latter is substantially authentic.
There is a readable account of Coppernicus, as well as of several other astronomers, in Bertrand's Fondateurs de l'Astronomie Moderne; but I have not used the book as an authority.
Chapter V.— For the life of Tycho I have relied chiefly on Dreyer's Tycho Brahe, which has also been used as a guide to his scientific work; but I have made constant reference to the original writings: I have also made some use of Gassendi's Vita
