SKETCH OF WILLIAM HUGGINS. 265 



dredth, a two-hundredth, a five-hundredth, or even a thousandth 

 part of the whole." Doppler had also, in 1841, suggested that on 

 the same principle on which a sound should become sharper or 

 flatter if there were an approach or a recession between the ear 

 and the source of the sound would apply equally to light ; and 

 Fizeau, about eight years later, had pointed out the importance 

 of considering the individual wave-lengths of which white light 

 is composed. Prof. Huggins was not able to continue his obser- 

 vations of this feature till 1872, when, having devised a trust- 

 worthy apparatus, and enjoying favorable weather, he applied his 

 method to fourteen stars which were found to have a motion of 

 approach and twelve which appeared to be receding. He re- 

 marked upon these results that the velocities of recession or ap- 

 proach assigned to the several stars by him represented the whole 

 of the motion in the line of sight existing between them and the 

 sun. As we know that the sun is moving in space, a part of 

 these observed velocities must be due to the solar motion. He 

 had not attempted to make this correction, because, although the 

 direction of the sun's motion seemed to be satisfactorily ascer- 

 tained, the velocity with which it was advancing rested on sup- 

 positions more or less arbitrary. It would be observed that, 

 speaking generally, the stars which the spectroscope showed to 

 be moving from the earth were situated in a part of the heavens 

 opposite to Hercules, toward which the sun was advancing ; while 

 the stars in the neighborhood of that region showed a motion of 

 approach. There were some exceptions to this general statement ; 

 and there were some other considerations which appeared to show 

 that the sun's motion in space is not the only, or even in all cases 

 the chief, cause of the observed proper motions of the stars. 

 There could be little doubt that in the observed stellar move- 

 ments we have to do with two other independent motions, namely, 

 a movement common to certain groups of stars, and a motion 

 peculiar to each star. 



Pertaining to other subjects than spectroscopic astronomy 

 on which Prof. Huggins has written, we notice a communication 

 to the Royal Society On the Function of the Sound-post, and 

 on the Proportional Thickness of the Strings of the Violin. A 

 curious letter from him in Nature, in 1873, relates the* case of a 

 family of dogs the members of which had inherited an antip- 

 athy to butchers' shops and butchers. Some of them could not 

 be induced to pass by a butcher's shop; others showed great 

 uneasiness in the presence of a butcher, although they could not 

 see him; and one of them attacked a gentleman visiting his 

 master, whose business was that of a butcher. In 1872 Dr. 

 Huggins edited and annotated an edition of Schellen's Spectrum 

 Analysis in its Application to Terrestrial Substances and the 



