240 Correspondence — Dr. Callaway. 



the longer paper (p. 228) seems to show that the abstractor has no 

 knowledge of crystalline rocks ; otherwise he would not suppose that 

 anyone could divide a series of limestones into gneisses, limestones, 

 and granitites ! Moreover, instead of reading the paper itself he has 

 made use of the abstract printed by the Geological Society before 

 the publication of the paper, and so actually credits the paper with 

 containing a discussion of the origin of the limestones which in 

 reality appeared elsewhere in a slightly modified form. 



In the case of both references the author's name is incorrectly 

 quoted. I should like also to take this opportunity of calling 

 attention to the numerous misprints which occur in the pages of the 

 Centralblatt fur Mineralogie, etc. ; see e.g. pp. 28, 29, 32, 60, 62 of 

 the current year's issue. A. K. Coomaraswamy. 



Peradexiya, Ceylon, March 2Zrd, 1903. 



PEOFESSOE, W. M. DAVIS AND EIVEE, CURVES. 



Sir, — Professor Davis, in your issue for April, criticizes my little 

 paper of October last, and offers an alternative theory. I laid down 

 the rule that, "in the vast majority of cases, the affluents of rivers 

 enter on the convex side of the curves." Mr, Davis admits the truth 

 of this rule (p. 148), and therefore his criticisms and his theory must 

 be consistent with it. 



He cites cases where affluents form deltas at their mouths, and the 

 main stream bends away from the tributary. Such exceptional 

 examples were discussed by me, but it seems scarcely logical ta 

 quote them as hostile to a theory which only professes to explain 

 cases where the rivers bend towards their affluents. 



Professor Davis attributes to me a belief in "an initially straight 

 main river." I did not assert, or even suggest, that such a thing 

 ever existed. I merely assumed straight courses for short distances. 

 We often get these even in oldish rivers, and they must have been 

 incomparably more frequent in new ones. I suppose that a river 

 has its tributaries even when it is young. If the shape of the ground 

 has given rise to a bend towards an affluent at this stage, my theory 

 is unnecessary. It is only required to account for the production of 

 a bend when the course happens to be straight, which must often 

 have been the case. 



But Professor Davis offers a theory of his own. He explains my 

 rule as due to the motion down the valley of the " meander system,"^ 

 so that, sooner or later, convex curves capture affluents entering on 

 the concave. But this is only possible, as shown by his explanation 

 and diagram (fig. 3, p. 147), where the meander system is in an 

 advanced stage. The coming in of most tributaries on the convex 

 curve has been determined much earlier. Professor Davis cannot 

 deny this without denying the rule, which is based upon the study 

 of rivers in all stages of development. His diagram (fig. 3) with 

 its crowd of affluents entering on the concaves is not true to nature,, 

 or to the rule which he concedes to be true to nature. I fail, 

 therefore, to see how the Professor's explanation can be " normal^ 

 effective, and fully verified." C. Callaway. 



Cheltenham, A^^ril, 1903. 



