[777] ‘All forces are radically of the same kind, and the distinction of them into living and dead is not grounded on just principles.’ Leslie on Heat, p. 133. Compare p. 299: ‘We shall perhaps find, that this prejudice, like many others, has some semblance of truth; and that even dead or inorganic substances must, in their recondite arrangements, exert such varying energies, and so like sensation itself, as if fully unveiled to our eyes, could not fail to strike us with wonder and surprise.’
[778] Mr. Napier, in his Life of Leslie, p. 17, says of it, very gravely, ‘Its hypotheses are not warranted by the sober maxims of inductive logic.’
[779] ‘Notwithstanding the contrary testimony, explicitly recorded by the founders of the English experimental school, he denied all merit and influence to the immortal delineator of the inductive logic.’ Napier's Life of Leslie, p. 42.
[780] The supposition, that volcanic agencies were formerly more potent than they are now, is by no means inconsistent with the scientific doctrine of uniformity, though it is generally considered to be so. It is one thing to assert the uniformity of natural laws; it is quite another thing to assert the uniformity of natural causes. Heat may once have produced far greater effects than it can do at present, and yet the laws of nature be unchanged, and the order and sequence of events unbroken. What I would venture to suggest to geologists is, that they have not taken sufficiently into account the theory of the interchange of forces, which seems to offer a solution of at least part of the problem. For, by that theory, a large portion of the heat which formerly existed may have been metamorphosed into other forces, such as light, chemical affinity, and gravitation. The increase of these forces consequent on the diminution of heat, would have facilitated the consolidation of matter; and until such forces possessed a certain energy, water, which afterwards became so prominent, could not have been formed. If the power of chemical affinity, for instance, were much weaker than it is, water would assuredly resolve itself into its component gases. Without wishing to lay too much stress on this speculation, I submit it to the consideration of competent judges, because I am convinced that any hypothesis, not absolutely inconsistent with the known laws of nature, is preferable to that dogma of interference, which what may be called the miraculous school of geologists wish to foist upon us, in utter ignorance of its incompatibility with the conclusions of the most advanced minds in other departments of thought.
The remarks in Sir Roderick Murchison's great work (Siluria, London, 1854, pp. 475, 476) on the ‘grander intensity of former causation,’ and on the difficulty this opposes to the ‘uniformitarians,’ apply merely to those who take for granted that each force has always been equally powerful: they do not affect those who suppose that it is only the aggregate of force which remains unimpaired. Though the distribution of forces may be altered, their gross amount is not susceptible of change, so far as the highest conceptions of our actual science extend. Consequently, there is no need for us to believe that, in different periods, the intensity of causation varies; though we may believe that some one agent, such as heat, had at one time more energy than it has ever had since.
[781] ‘The great agents of change in the inorganic world may be divided into two principal classes, the aqueous and the igneous. To the aqueous belong rain, rivers, torrents, springs, currents, and tides; to the igneous, volcanos and earthquakes. Both these classes are instruments of decay as well as of reproduction; but they may also be regarded as antagonist forces. For the aqueous agents are incessantly labouring to reduce the inequalities of the earth's surface to a level; while the igneous are equally active in restoring the unevenness of the external crust, partly by heaping up new matter in certain localities, and partly by depressing one portion, and forcing out another, of the earth's envelope.’ Lyell's Principles of Geology, 9th edit., London, 1853, p. 198.
[782] Dr. Whewell, comparing him with his great German contemporary, Werner, says, ‘In the German, considering him as a geologist, the ideal element predominated.’ … ‘Of a very different temper and character was William Smith. No literary cultivation of his youth awoke in him the speculative love of symmetry and system; but a singular clearness and precision of the classifying power, which he possessed as a native talent, was exercised and developed by exactly those geological facts among which his philosophical task lay.’ … ‘We see great vividness of thought and activity of mind, unfolding itself exactly in proportion to the facts with which it had to deal.’ … ‘He dates his attempts to discriminate and connect strata from the year 1790.’ Whewell's History of the Inductive Sciences, London, 1847, vol. iii. pp. 562–564.
[783] ‘The execution of his map was completed in 1815, and remains a lasting monument of original talent and extraordinary perseverance; for he had explored the whole country on foot without the guidance of previous observers, or the aid of fellow-labourers, and had succeeded in throwing into natural divisions the whole complicated series of British rocks.’ Lyell's Principles of Geology, p. 58. Geological maps of parts of England had, however, been published before 1815. See Conybeare on Geology, in Second Report of the British Association, p. 373.
[784] ‘A great body of new data were required; and the Geological Society of London, founded in 1807, conduced greatly to the attainment of this desirable end. To multiply and record observations, and patiently to await the result at some future period, was the object proposed by them; and it was their favourite maxim, that the time was not yet come for a general system of geology, but that all must be content for many years to be exclusively engaged in furnishing materials for future generalizations.’ Lyell's Principles of Geology, p. 59. Compare Richardson's Geology, 1851, p. 40.
[785] Cuvier, in his Life of Werner, says (Biographie Universelle, vol. i. pp. 376, 377), ‘La connaissance des positions respectives des minéraux dans la croûte du globe, et ce que l'on peut en conclure relativement aux époques de leur origine, forment une autre branche de la science qu'il appelle Géognosie. Il en présenta les premières bases en 1787, dans un petit écrit intitulé “Classification et description des Montagnes.”’