A. SYNOPSIS 



OF THE SCIENTIFIC WRITINGS OF SIR WILLIAM HERSCHEL. 



By Edward S. Holden and Charles S. Hastings. 



I,— Introductory Note. 



The astronomical life of Sir William Herschel covered forty two 

 years. During this period he published no less than sixty-nine different 

 memoirs, which are scattered through the annual volumes of the Philo- 

 sophical Transactions of the Royal Society of London from 1780 to 181S. 



Two generations have passed since his death, and we have no readier 

 means of studying his works than in the original volumes of the Trans- 

 actions, now become rare and costly. Students of astronomy and physics 

 are thus often compelled to know his writings at second- hand from text- 

 books, and not in the vigorous and ardent style of the original. The 

 text-books also frequently quote him incorrectly, and have thus helped 

 to spread erroneous notions not only of what he said, but of the facts 

 themselves. 



Herschel's long life was all too short, and his assistance was too 

 small to allow him to put even his ijublished work into a final definite 

 form. He has once given us a hint of what he desired, and it seems 

 scarcely less than a duty for his successors to carry out his wishes. 



At the end of his memoir of 1811, Herschel added a synopsis of its 

 contents made paragraph by paragraph ; this synopsis (which is given at 

 pages 87-80 of this worlc) serves to summarize and to enforce his. views, 

 and to condense his arguments. His style lends itself to tliis condensa- 

 tion. The synopsis of 5 pages contains all the material facts of the 

 main paper of G7 pages, and the course of the argument can be plainly 

 followed. 



In the absence of an edition of Herschel's collected works, a want 

 whose fulfillment still seems far oft', we have thought that we could 

 hardly render a better service than to carry out for all of his writings 

 the idea which he executed for only one. The model has been set by 

 himself. We have simply followed this, and have given a synopsis of 

 each of his memoirs in the Philosophical Transactions, following his own 

 plan. The papers on astronomical subjects have been condensed by 

 Professor Holden; those on physics by Dr. Hastings. The Avorks of 

 Herschel published elsewhere have not been included in the synopsis, 

 as they are comparatively unimijortant. 



