A. R. Hunt — Nomenclature of Rlpple-mark. 411 



In my recapitulation I wrote, " Marine ripple-marks are formed by 

 alternate currents set up by waves" (Proc. Roy. Soc, 1882, p. 18). 



In 1883 three vei-y important papers were published on the 

 subject by MM. De Candolle and Forel and by Professor G. H. 

 Darwin, F.R.S. Thus, in March, 1884, less than two years after 

 the publication of my own pioneer paper, I was able in a paper on 

 Sea Beaches and Sea Bottoms to direct the attention of students of 

 wave-action to the three important papers referred to above, and 

 also to some earlier observations of Professor Forel published in the 

 Bulletin de la Socieie Vaudoise, etc., for February and March, 1878. 

 The last-named publications give Prof. Forel the right of priority 

 so far as wave-current ripple-mark is concerned. 



Professor Darwin went further than any previous experimenter 

 by demonstrating the action of eddies and vortices in collecting 

 loose sand into ripple-mark, as soon as the incipient ripple-marks 

 are established. Previous observers had indicated the agents,^ 

 viz. wave -currents, but Professor Darwin demonstrated their mode 

 of action 



As soon as the above papers appeared Sir Archibald Geikie 

 allowed them their full weight, as will appear by a comparison 

 of the third and fourth editions of his textbook with earlier works. 

 For instance, to be as brief as possible, in the Manual of 1872 

 (Jukes & Geikie) we read : — Ripple-mark " is produced on the 

 sea-beach .... because of the moving current of water as 

 the tide advances or recedes" (p. 192). 



In Sir Archibald's first edition of his Textbook we read : — 

 " Water (or air) gently agitated in a given direction [italics minej 

 throws the surface of sediment into ripples. . . . Their 

 general direction . . . suffices to indicate the quarter whence 

 the chief movement of the water has come " (p. 483). 



In the Textbooks of 1893 and 1903 there is a complete revolution. 

 We now read : " They have been produced by an oscillation of the 

 medium (water or air) in which the loose sand has lain. In water 

 an oscillatory movement, sometimes also with a more or less marked 

 current, is generated by wind blowing on its surface. The sand 

 grains are carried backwards and forwards. By degrees inequalities 

 of surface are produced which give rise to vortices in the water. 

 . . . . In regular ripple-mark the forms are produced by water 

 oscillating i-elatively to the bottom and the consequent establishment 

 of a series of vortices." 



No one without a minute study of ripple-mark could appreciate 

 the extreme accuracy of phraseology and description in the above 

 few lines. I may, however, remark that the ' alternate currents, '^ 

 for which I contended single-handed in 1882, are the actual currents 

 in opposite directions set up by waves, and not the reversal of the 

 direction of a steady current of wind or water created locally by 

 vortices. 



I need scarcely express my deep sense of gratitude to Sir Archibald 

 Geikie for having so promptly recognised the importance of very 

 unorthodox doctrines at a time when it was almost impossible to 

 obtain a patient hearing for them in England. 



