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Show 62 HUTTONIAN THEORY. aspect from that of ordinary lava, he attributed to t?eir having 1 d down under the pressure of the sea, and m order to coo e h' h' f . d remove the obJi ections started against t IS th• eory, •I s nen• S.I r J a mes Hall instituted a most curious and mstructive series 1 . of chemical experiments, illustrating the crystal me arrange-nt and texture assumed by melted matter cooled down under me 'fi . . . d high pressure. The absence of strat1 catlo~ m gramte, an its analogy in mineral character to rocks wInch h.e deemed of igneous origin, led Hutton to conclude that gr~m~e must also have been formed from matter in fusion, and this mference he felt could not be fully confirmed, unless he discovered at the contact of granite and other strata a repetition of the phenomena exhibited so constantly by the trap-rocks. Resolved to try his theory by this test, he went t~ the Grampians and surveyed the line of junction of the gramte and supermcumbent stratified masses, and found in Glen Tilt in 1785 the most clear and unequivocal proofs in support of his views. ,V e!ns of red granite are there seen branc~ing out fro~ the pn~c1pal ~ass, and traversing the black . miCaceous sch1st and prtmary hmestone. The intersected stratified rocks are so distinct in colour and appearance as to render the example in that locality most striking, and the alteration of the limestone in contact was very analogous to that produced by trap veins on calcareous strata. This verification of his system filled him with delight, and called forth such marks of joy and exultation, that the guides who accompanied him, says his biographer, were convinced that he must have discovered a vein of silver or gold #.', He was aware that the same theory would not explain the origin of the primary schists, but these he called primary, rejecting the term primitive, and was disposed to consider them as sedi .. mentary rocks altered by heat, and that they originated in some other form from the waste of previously existing rocks. By this important discovery of granite veins to which he had been led by fair induction from an independent class of facts; Hutton prepared the way for the greatest innovation on the systems of his predecessors. Vallisneri had pointed out the general fact, that there were certain fundamental rocks which contained no organic remains, and which he supposed to have been formed "' Playfa.ir's Works, vol, iv., p. 75. HUTTONIAN THEORY. 63 before the creation of Jiving beings. Moro, Generelli, and other Italian writers embraced the same doctrine, and Lehman regarded the mountains called by him primitive, as parts of the original nucleus of the globe. The same tenet was an article of faith in the school of Frey berg; and if any one ventured to doubt the possibility of our being enabled to carry back our researches to the creation of the present order of things., the granitic rocks were triumphantly appealed to. On them seemed written in legible characters, the memorable inscription Dinanzi a me non fur cose create Se non eterne, and no small sensation was excited when Hutton seemed, with unhallowed hand, desirous to erase characters already regarded by many as sacred. " In the economy of the world,'' said the Scotch geologist, " I can find no traces of a beginning, no prospect of an end;" and the declaration was the more startlinO' when coupled with the doctrine, that all past changes on th~ globe had been brought about by the slow agency of existing causes. The imagination was first fatigued and overpowered by endeavouring to conceive the immensity of time required for the annihilation of whole continents by so insensible a pro~ ess. ! et when the thoughts had wandered through these mtermmable periods, no resting place was assigned in the remotest distance. The oldest rocks were represented to be of a derivative nature, the last of an antecedent series, and that perhaps one of many pre-existing worlds. Such views of the i'm~ensity of past time, like those unfolded by the Newtonian philosophy in regard to space, were too vast to awaken ideas of subli~ity unmixed with a painful sense of our incapacity to conceive a plan of such infinite extent. Worlds are seen beyond worlds immeasurably distant from each other, and beyond them all innumerable other systems are faintly traced on the confines of the visible universe. The characteristic feature of the Huttonian . theory was, as before hinted, the exclusion of all causes not supposed to belong to the present order of nature. Its greatest defect consisted in the undue influence attributed to subterranean heat, which was supposed necessary for the consolidation of all submarine deposits, Hutton made no step beyond Hooke, Moro, and |