tude toward such criticisms as had then appeared, to be as follows: "I had been frequently invited to write on Glaciers in encyclopædias, journals, and magazines, but had always declined to do so. I had also abstained from making them the subject of a course of lectures at the Royal Institution, wishing to take no advantage of my position there, and indeed to avoid writing a line or uttering a sentence on the subject for which I could not be held personally responsible. In view of the discussions which the subject had provoked, I thought this the fairest course.
"But, in 1871, the time (I imagined) had come when, without risk of offense, I might tell our young people something about the labors of those who had unraveled for their instruction the various problems of the ice-world. My lamented friend and ever-helpful counselor, Dr. Bence Jones, thought the subject a good one, and accordingly it was chosen. Strong in my sympathy with youth, and remembering the damage done by defective exposition to my own young mind, I sought, to the best of my ability, to confer upon these lectures clearness, thoroughness, and life.
"I aimed, indeed, at nothing less than presenting to my youthful audience, in a concentrated but perfectly digestible form, every essential point embraced in the literature of the glaciers, and some things in addition, which, derived as they were from my own recent researches, no book previously published on this subject contained. But my theory of education agrees with that of Emerson, according to which instruction is only half the battle: what he calls provocation being the other half By this he means that power of the teacher, through the force of his character and the vitality of his thought, to bring out all the latent strength of his pupil, and to invest with interest even the driest matters of detail. In the present instance, I was determined to shirk nothing essential, however dry; and, to keep my mind alive to the requirements of my pupil, I proposed a series of ideal ramblings, in which he should be always at my side. Oddly enough, though I was here dealing with what might be called the abstract idea of a boy, I realized his presence so fully as to entertain for him, before our excursions ended, an affection consciously warm and real.
"A German critic, whom I have no reason to regard as specially favorable to me or it, makes the following remark on the style of the book: 'This passion' (for the mountains) 'tempts him frequently to reveal more of his Alpine wanderings than is necessary for his demonstrations. The reader, however, will not find this a disagreeable interruption of the course of thought; for the book thereby gains wonderfully in vividness.' This, I would say, was the express aim of the breaks referred to. I desire to keep my companion fresh as well as instructed, and these interruptions were so many breathing-places where the intellectual tension was purposely relaxed and the mind of the pupil braced to fresh action.
