316 scrambles amongst the alps.

“ that he was convinced that the glaciers of the Alps werecompetent to scoop out the valleys of the Alps, ” * and I amunaware that his opinions have undergone any alterationsince that time. In 1869 he gave a hard side-blow toProfessor Ramsay, in Macmillan's Magazine , by provingthat some existing Alpine glaciers exercise little or noerosion upon their beds near and at their terminations(snouts), because at such places they are almost stationary, t

It is impossible to criticize these two theories at the samemoment. Both of them agree in attributing enormouspowers of excavation to glaciers, but they disagree totallyand completely as to the modus operandi by which theeffects were produced. They differ even in their generalconclusions. One asserts that the greatest effects wereproduced upon the plains, and that very little was doneamongst the mountains; whilst the other declares thatthe mountains owe their actual forms to the carving ofglaciers, and that the plains did not suffer at all! Thereis no wonder that the unenlightened public inquire, “ Whoshall decide between the disagreements of these doctors ? ”But it is surprising to find some persons still accept asgospel truth the contradictory dicta of these eminent men,and speak and write as if it were established that lakebasins and mountain valleys have been excavated byglaciers.

It is not requisite to decide between all the differencescontained in these two theories, in order to arrive at atolerably correct judgment upon the general conclusions.Professor Ramsay, for example, attributes the production ofthe greatest effects to the weight of glaciers. ProfessorTyndall, on the other hand, assigns most power to themotion. I shall ignore these points, because I have nodata from which to arrive at a satisfactory decision, and

* Birmingham Daily Post, September 13, 1865.

t It must not be understood that anything of the nature of acontroversy was carried on, in the magazines cited, by the twoProfessors. They did not refer to each other by name: but it wasimpossible to read the passages which have been quoted, without feelingthat they were intended to be replies to objections on the other side.