692 



SCIENCE 



[N. S. Vol. XXIX. No. 748 



flowing in the external circuit depends on the 

 specific gravity of the zinc sulphate, and that 

 polarization in the battery is caused by the 

 saturation of the zinc sulphate. 



He made important investigations concern- 

 ing the velocity of the electric current, and 

 showed that the apparent velocity is directly 

 proportional to the magnetic force of the cir- 

 cuit, but the real velocity can not be measured. 

 In 1869 he was chief of an expedition of 

 astronomers sent to Matoon, HI., to observe 

 the total eclipse of the sun. 



In 1870 he was married to Emma C. Shear, 

 daughter of Jacob H. Shear, of Albany, 

 N. Y. 



He was elected an honorary member of the 

 German Astronomical Society in 1871. Al- 

 most from the beginning of his professional 

 career he took an active part in the meetings 

 of the American Association for the Advance- 

 ment of Science, and was at one time vice- 

 president. 



In the year 1879 he was appointed director 

 of the Dearborn Observatory at Chicago and 

 professor of astronomy in the old Chicago 

 University. His work at once brought Dear- 

 born Observatory into special prominence 

 among the leading observatories of the world. 

 It was then that he began his systematic 

 study of the planet Jupiter, and this series of 

 observations was continued without interrup- 

 tion for thirty years till the time of his death. 

 These observations included a careful study 

 by micrometer measurements of all the jovian 

 phenomena, especially of the great red spot 

 and the equatorial belts, and made Professor 

 Hough justly famous in the latter days of his 

 life as the greatest authority for that planet. 

 The details and results of these investigations 

 are to be found in the various annual reports 

 of the Chicago Astronomical Society, and in 

 numerous pamphlets published after he came 

 to Evanston. 



He also made observations of the satellites 

 of Uranus, and discovered a few new nebulae. 

 During the first few years in Chicago he was 

 associated in his work with Professor Colbert 

 and Professor Burnham. 



In 1882 he took up the study of difficult 

 double stars, and is credited with having dis- 



covered over 600 pairs, most of them beyond 

 the reach of any but the most powerful tele- 

 scopes, which gave him the distinction of 

 having discovered more double stars than any 

 other astronomer of his time. 



While in Chicago he perfected his printing 

 chronograph, an instrument which is coming 

 into general use in observatories. He also in- 

 vented an observing seat for the equatorial, 

 which has been adopted by all the leading 

 observatories. 



He became interested in the Chicago Acad- 

 emy of Sciences, and served one term as vice- 

 president of that institution. 



In 1887 the Dearborn Observatory was 

 moved to Evanston and became part of the 

 Northwestern University. Professor Hough 

 came with it as director, and as professor of 

 astronomy in Northwestern University. Dur- 

 ing his twenty-one years' residence in Evans- 

 ton he accomplished a large part of his impor- 

 tant work on Jupiter and double stars. 



In 1888 he invented a new astronomical 

 dome, superior to anything else of the kind. 

 His inventions here include an absolute sensi- 

 tometer for testing photographic plates in 

 various kinds of light, an electrical control 

 for the equatorial, an improved form of 

 storage battery combining durability and low 

 cost, a transmission dynamometer for use with 

 the electric motor, and a new and improved 

 form of photographic plate-holder. 



In 1891 he received the honorary degree of 

 doctor of laws from Union Colleg-e, and about 

 the same time was elected a member of the 

 British Astronomical Association. At the 

 "World's Congress in Chicago in 1893 he was 

 president of the mathematical and astronom- 

 ical section. In 1903 he was elected an asso- 

 ciate member of the Eoyal Astronomical So- 

 ciety of England. He was also a member of 

 the Astronomical Society of the Pacific, the 

 Astronomical and Astrophysical Society, the 

 American Philosophical Society, the Amer- 

 ican Institute of Civics, the Chicago Photo- 

 graphic Society and the Trinity Historical 

 Society of Texas, and at one time a member 

 of the Albany Institute, the Chicago Lantern 

 Slide Club and the Chicago Electrical Society. 



In character Professor Hough was quiet 



