JAMES EDWARD KEELEE. 87 



the Allegheny Observatory, affording most efficient help to Professor 

 Langley in his classical researches on the lunar heat and on the infra- 

 red portion of the solar spectrum. 



Early in 1886, on Professor Holden's recommendation, Keeler was 

 appointed assistant to the Lick trustees. He arrived at Mt. Hamilton 

 on April 25, 1886, and immediately proceeded to establish the time 

 service. The telegraph line to San Jose was perfected, the transit in- 

 strument, the clocks and the sending and receiving apparatus at both 

 ends of the line were installed. The signals were sent out on and after 

 January 1, 1887, north to Portland, east to Ogden and south to San 

 Diego and El Paso. In addition to the time service, he assisted the 

 trustees in installing the various instruments. 



When the observatory was completed and transferred to the regents 

 of the University of California, on June 1, 1888, Mr. Keeler was ap- 

 pointed astronomer: the original staff consisting of Astronomers Holden, 

 Burnham, Schaeberle, Keeler and Barnard, and Assistant Astronomer 

 Hill. 



Professor Keeler was placed in charge of the spectroscopic work of 

 the observatory. The large star spectroscope, constructed mainly from 

 his designs, has no superior for visual observations. Of the many results 

 obtained with this instrument we may mention the observations of 

 Saturn's rings and Uranus, with reference to their atmospheres; of 

 the bright and dark lines in the spectra of y Cassiopeia? and /? Lyra?; 

 of the color curve of the 36-inch equatorial, and of the spectra of 

 the Orion Nebula and thirteen planetary nebula?. 



His beautiful observations on the velocities in the line of sight of 

 these fourteen nebula? mark a distinct epoch in visual spectroscopy. His 

 memoir on the subject took its place as a classic at once. The probable 

 error of the final result for each nebula, based on the mean of several 

 observations, is only 3.2 kilometers per second. Attention should be 

 called to one extremely important fact established by these measures, 

 viz., the velocities of the nebulae in their motion through space are of 

 the same order of magnitude as the velocities of the stars. 



The recognition of the fact that a great refracting telescope is also 

 a most powerful spectroscope for special classes of objects, by virtue of 

 the chromatic aberration of the objective, is due to Professor Keeler. 

 Among the first objects observed with the 36-inch equatorial were the 

 planetary nebula? and their stellar nuclei. The observers were struck 

 with the fact that the focal length for a nebula is 0.4 inch longer than 

 for its stellar nucleus; a discrepancy which Professor Keeler at once ex- 

 plained by recalling that the star's light is yellow, whereas that of the 

 nebula is greenish-blue. 



Astronomical readers will remember Keeler's splendid drawings of 

 the planets Saturn, Jupiter and Mars, made with the assistance of the 



