1880.] 



President's Address. 



95 



lead liim to an arrangement of the stars in a continuous series according 

 to the breadth and marginal differences of the typical lines, particularly 

 of the K line. Mr. Lockyer continues his researches on dissociation, as 

 indicated in solar outbursts, and in connexion with this work is 

 engaged on a systematic observation of the spectra of sun-spots. At 

 the request of the Committee on Solar Physics, corresponding obser- 

 vations are being made at Greenwich. 



From the series of Greenwich photographs of the sun, 1874 — 1879, 

 the mean heliographic latitude of spots and mean distance from the 

 sun's equator, have been deduced for each rotation and for each year. 

 (" Greenwich Spectroscopic and Photographic Results, 1879.)" 



A fine 36-inch silver-on-glass reflector has been recently constructed 

 by Mr. Common, and with this instrument he has obtained photo- 

 graphs of Jupiter, showing the red spot, and of the satellites. (" Obser- 

 vatory," No. 34) 



At the outset of an undertaking one figures to oneself in imagina- 

 tion what may be done ; towards the close of it one sees in actual fact 

 what has been done. In commencing this address I had hoped to say 

 something of the progress of mathematics ; before bringing it to a 

 conclusion, I find my space filled and my time exhausted. How far 

 the good intentions of this year may be realised in the next, cannot 

 yet be seen ; but the difficulties of a task do not always diminish the 

 fascination of making an attempt. 



On the motion of Mr. Scott Russell, seconded by Mr. Merrifield, it 

 was resolved : — " That the thanks of the Society be returned to the 

 President for his Address, and that he be requested to allow it to be 

 printed." 



The President then proceeded to the presentation of the Medals : — 



The Copley Medal has been awarded to Professor James Joseph 

 Sylvester, F.R.S. His extensive and profound researches in pure 

 mathematics, especially his contributions to the Theory of Invariants 

 and Co variants, to the Theory of Numbers, and to Modern Geometry, 

 may be regarded as fully establishing Mr. Sylvester's claim to the 

 award of the Copley Medal. 



A Royal Medal has been awarded to Professor Joseph Lister, 

 F.R.S. Mr. Lister's claims to the honour of a Royal Medal are based 

 upon his numerous and valuable contributions to physiological and 

 biological science during the last thirty years. 



By permission of its author, the Fellow of the Society best 

 qualified, by his own extensive researches on the germ theory, to 

 form a judgment, I quote the following account of Professor Lister's 

 work and achievements : — 



