18 



Prof. G. H. Darwin. 



[Nov. 22,, 



November 22, 1883. 

 Professor T. H. HUXLEY, President, in the Chair. 



In pnrsnance of the Statutes, notice was gi^en from the Chair of 

 t he ensuing Anniversary Meeting, and the list of Officers and Council 

 nominated for election, was read as follows : — 



President. — Professor Thomas Henry Huxley, LL.D. 

 Treasurer. — John Evans, D.C.L., LL.D. 



o . / Professor George Gabriel Stokes, M. A., D.C.L., LL.D. 



o ecretcivies. s -»«-.-. -. -r-. -.»•'« r 



L Professor Michael Foster, M.A., M.D. 



Foreign Secretary. — Professor Alexander William Williamson, LL.D. 



Other Members of the Council. — Captain W. de Wiveleslie Abney, 

 R.E.; Professor W. Grylls Adams, M.A., F.C.P.S. ; the Duke of 

 Argyll, K.T., D.C.L. ; John Gilbert Baker, F.L.S.; Thomas Lauder 

 Brunton, M.D., Sc.D. ; William Henry M. Christie, Astron. Boyal; 

 Warren De La Rue, M.A., D.C.L. ; Sir Frederick J. 0. Evans, K.C.B. ; 

 Professor George Carey Foster, B.A. ; Francis Galton, M.A., F.G.S. ;. 

 James Whitbread Lee Glaisher, M.A. ; Sir William Withey Gull,. 

 Bart., M.D. ; Hugo Miiller, Ph.D. ; Professor Joseph Prestwich,, 

 M.A., F.G.S. ; Professor Osborne Reynolds, M.A. ; Osbert Salvin,. 

 M.A., F.L.S. 



The Presents received were laid on the table, and thanks ordered 

 for them. 



The following Papers were read : — 



I. " On the Formation of Ripple-mark in Sand." By G. H„ 

 Darwin, F.R.S., Plumian Professor and Fellow of Trinity 

 College, Cambridge. Received October 18, 1883. 



The following paper contains an account of experiments and obser- 

 vations on the formation of ripple-mark in sand. The first section is 

 devoted to experiments on the general conditions under which ripple- 

 mark is formed, and especially on the mode of formation and main- 

 tenance of irregular ripples by currents. In the second section it is 

 shown that regular ripple-mark in sand is due to a complex arrange- 

 ment of vortices in oscillating water; and the last section gives some 

 account of the views of certain recent observers in this field, and a 



