SKETCH OF WILLIAM HUGGINS. 261 



means of conducting investigations of this kind, which his prede- 

 cessors had not possessed, was offered in the method of spectrum 

 analysis discovered by Kirchhoff ; and he was first able to under- 

 take the application of this method in the beginning of 1862. In 

 preparation for the research he mapped the spectra of twenty-six 

 of the chemical elements, publishing the results of his labors in 

 the Philosophical Transactions of the Royal Society. In con- 

 junction with Dr. William Allen Miller, he compared the spectra 

 of some fifty stars with those of several terrestrial elements, and 

 found that the stars are hot bodies, similarly constituted with our 

 sun, and containing many of the substances found on the earth. 

 In 1864 he and Prof. Miller reported to the Royal Society the 

 results of their observations of the spectra of the planets Venus, 

 Mars, Jupiter, and Saturn ; but they had found the light from 

 Uranus too faint to be satisfactorily examined with the spectro- 

 scope. 



The study of Uranus was resumed with an improved tele- 

 scope in 1871 by Mr. Huggins, and he found its spectrum to be 

 continuous so far as the feebleness of its light permitted it to be 

 traced, or from C to near G. A photograph of the spectrum of 

 Sirius was obtained by Mr. Huggins and Prof. Miller in 1863, 

 when observations were suspended. They were resumed by Mr. 

 Huggins in 1876, with apparatus so arranged that the spectrum 

 of the sun could be taken on the same plate, and this method 

 was applied to other bright stars. After recording in his com- 

 munication to the Royal Society his expectation, with apparatus 

 then under construction, of obtaining finer lines which might be 

 present in the stellar light than those that had been seen, and of 

 extending the photographic method to stars that were less bright, 

 Prof. Huggins referred in general terms to " the many important 

 questions in connection with which photographic observations 

 of stars may be of value." Another paper recording the progress 

 of these investigations to the end of 1879 named thirteen bright 

 stars, Venus, Mars, and Jupiter, and different small areas of the 

 moon, to which the method had been applied. Six of the spectra 

 belonged to stars of the white class, while Arcturus seemed to 

 present a spectrum " on the other side of that of the sun in the 

 order of changes from the white-star group." The photographs 

 of the planets showed no sensible planetary modification of the 

 violet and ultra-violet parts of the spectrum. The results of the 

 photographs of lunar areas taken under different conditions of 

 illumination were negative as to any absorptive action of a lunar 

 atmosphere. The author was then preparing to attempt to obtain 

 by photography any lines which might exist in the violet and 

 ultra-violet spectra of the gaseous nebulae. He further pointed 

 out " the suitability of the photographic method of stellar spec- 



