292 Simon Newcomb. 



by Newcomb in his studies of telescopes made him an invalua- 

 ble adviser in the equipment of the Lick Observatory. 



This grand project of Newcomb led to two other extensive 

 investigations which a man of less intellectual breadth and 

 courage might have been expected to leave to others. For a 

 long time there had been growing a doubt among astronomers 

 as to the accuracy of the accepted value of the fundamental 

 unit of the Solar System, namely, the true distance of the Sun 

 from the Earth. This value was established by Encke from 

 observations of the transits of Yenus. Newcomb undertook 

 the enormous labor of a complete rediscussion of this result 

 from all the original records of the observations of transits of 

 Yenus previous to that of 1882, and, from a judicial weighing 

 of probabilities which has commanded admiration from all 

 competent critics, derived a value which was almost identical 

 with that now accepted. 



An independent method of establishing the same constant is 

 derived by combining the observed aberration of light with its. 

 measured velocity. Professor Michelson, then an Ensign in 

 the Navy, had improved Foucault's method of measuring the 

 velocity of light and, by a series of skillful experiments, had 

 added greatly to the precision of our knowledge of its value. 

 Newcomb secured Michelson's aid and a grant of money from 

 Congress to meet the expenses of a continuation of these 

 measures on the largest effective scale. The results of such 

 cooperation were most brilliant, and they attach the name of 

 the astronomer to the historical determinations of the great 

 constant of physical science as w^ell to that of astronomy. 



The world of science has not failed to recognize and reward, 

 as far as possible, the great services of Simon Newcomb. In 

 our own country hardly a university of prominence has with- 

 held from him its highest honors. The Institute of France 

 made him a correspondent in 1874, and in 1893 elected him as 

 one of its associates, an honor accorded to only eight outside of 

 France. An Officer of the Legion of Honor in 1893, he was 

 made a Commander in 1907. In our own country Professor 

 Newcomb was very active in the National Academy, in the 

 American Philosophical Society, in the Astrophysical Society, 

 and in others. A man delightfully simple in manner and 

 cordial in intercourse with other men of science, it was always 

 an inspiration to younger men to converse with him. 



C. S. H. 



Samuel William Johnson, Professor of agricultural chemis- 

 try in the Sheffield Scientific School of Yale University, died on 

 July 21, in his eightieth year. A notice is deferred till a later 

 number. 



