1880.] 



President's Address. 



99 



researches. He is tlie author of papers which have been translated 

 into most European languages on subjects of gunnery and gunpowder; 

 he is perhaps the highest authority we possess on the higher branches 

 of artillery science, and the best known on the Continent. His great 

 talents and attainments are not more conspicuous than his singular 

 modesty, and his indefatigable industry. He has been engaged on 

 these subjects about twenty years, having published the first experi- 

 ments in this country with Navez' eleciroballistic apparatus, in 1862. 



The Runrford Medal has been awarded to Dr. William Huggins, 

 I\R.S. In 1866, a Royal Medal was awarded to Dr. Huggins for his 

 important researches. Since that time he has been continually 

 engaged in prosecuting his investigations and in extending them over 

 a wider range. Thus he has determined the radial component of the 

 velocity of the heavenly bodies relatively to our earth, by means 

 of the alteration of the refrangibility of certain definite kinds of 

 light which they emit, or which are stopped by their atmospheres. 

 The smallness of the alteration corresponding to a relative velocity 

 comparable with the velocity of the earth in its orbit makes the deter- 

 mination a matter of extreme delicacy. But as early as 1868, he 

 had obtained such trustworthy determinations, that he was able to 

 announce before the Royal Society that Sirius was receding from our 

 solar system with a velocity of about 29*94 miles per second. 



In a paper presented to the Royal Society in 1872, he has given the 

 results obtained for a large number of stars, and has shown that sOme 

 are receding and some approaching, and that there seems to be 

 a balance of recession in those parts of the heavens, from which we 

 have reason, from the observed proper motions, which of course can 

 only be transversal, to conclude that the solar system is receding, and 

 a balance in favour of approach in the opposite direction ; while yet 

 it does not appear that the motion of the solar system would alone 

 account for the whole of the proper motions of the stars in a radial 

 direction. 



The same inquiry was extended to the nebulae, the spectrum of 

 which consists of bright lines, and in this case it presented greater 

 difficulties. As those nebular lines which appear pretty certainly to be 

 identifiable with hydrogen, are too faint to be employed in the in- 

 vestigation, and the others are not at present identified with those of 

 any known element or compound, he was obliged to avail himself of a 

 coincidence between the brightest nebular line and a line of lead. But 

 as the coincidence is probably merely fortuitous, the results give only 

 the differences of approach or recess of different nebulas. The observa- 

 tions seem to show that, so far as has been observed, the nebulaa are 

 objects of greater fixity as regards motion in space, than the stars. 



The other subject to which Dr. Huggins has more particularly 



