And the book pretends to be so explanatory, too, to his young friends!--explanatory of the use of the theodolite, of the nature of presence of mind, of the dependence of enjoyment of scenery upon honest labour, of the necessity that in science, "thought, as far as possible, should be wedded to fact," and of the propriety of their becoming older and better informed before they unqualifiedly accept his opinion of the labours of Rendu! But the one thing which, after following him through the edification of his four hundred and ten sentences, they had a right to have explained to them--the one thing that will puzzle them if ever they see a glacier, "how the centre flows past the sides, and the top flows over the bottom," the Professor does not explain; but only assures them of the attention which the experiments of Mr. Mathews, Mr. Froude, and above all Signor Bianconi, on that subject, "will doubtless receive at a future time." The readers of 'Fors' may imagine they have nothing to do with personal questions of this kind. But they have no conception of the degree in which general science is corrupted and retarded by these jealousies of the schools; nor how important it is to the cause of all true education, that the criminal indulgence of them should be chastised. Criminal is a strong word, but an entirely just one. I am not likely to overrate the abilities of Professor Tyndall; but he had at least intelligence enough to know that his dispute of the statements of Forbes by quibbling on the word "viscous" was as uncandid as it was unscholarly; and it retarded the advance of glacier science for at least ten years. It was unscholarly, because no other single word existed in the English language which Forbes could have used instead; and uncandid, because Professor Tyndall knew perfectly well that Forbes was aware of the difference between ice and glue, without any need for experiments on them at the Royal Institution. Forbes said that the mass of glacier ice was viscous, though an inch of ice was not, just as it may be said, with absolute truth, that a cartload of fresh-caught herring is liquid, though a single herring is not. And the absurdity as well as the iniquity of the Professor's wilful avoidance of this gist of the whole debate is consummated in this last book, in which, though its title is "The Forms of Water," he actually never traces the transformation of snow into glacier ice at all--(blundering by the way, in consequence, as to the use of one of the commonest words in Savoyard French, névé). For there are three great "forms of water" by which the Alps are sheeted,--one is snow; another is glacier ice; the third is névé, which is the transitional substance between one and the other. And there is not a syllable, from the beginning of the book to the end, on the subject of this change, the nature of which is quite the first point to be determined in the analysis of glacier motion.