ESSENTIAL AND ECULIAR. 



65 



estly directed the whole acumen of their intellect, how absurd, how con- 

 temptible is the fond confidence of common life ! Yet what, indeed, when 

 fairly estimated by the survey that has now been briefly taken of the sensible 

 universe, — what is the aggreg^ate opinion, or the aggregate importance of the 

 whole human race ! We call ourselves lords of the visible creation : nor 

 ought we at any time, with affected abjection, to degrade or despise the high 

 gift of a rational and immortal existence. — Yet, what is the visible creation ? 

 by whom peopled ? and where are its entrances and outgoings 1 Turn wher- 

 ever we will, we are equally confounded and overpowered : the little and the 

 great are alike beyond our comprehension. If we take the microscope, it un- 

 folds to us, as I observed in our last lecture, living beings, probably endowed 

 with as complex and perfect a structure as the whale or the elephant, so 

 minute that a million of millions of them do not occupy a bulk larger than^a 

 common grain of sand. If we exchange the microscope for the telescope, 

 we behold man himself reduced to a comparative scale of almost infinitely 

 smaller dimension, fixed to a minute planet that is scarcely perceptible 

 throughout the vast extent of the solar system ; while this system itself forms 

 but an insensible point in the multitudinous marshallings of groups of worlds 

 upon groups of worlds, above, below, and on every side of us, that spread 

 through all the immensity of space, and in sublime, though silent harmony 

 declare the glory of God, and show forth his handy work. 



LECTURE VI. 



ON GEOLOGY. 



There are some subjects on which the philosopher is obliged to exercise 

 nearly as much imagination as the poet ; for it is the only faculty by which 

 he can expatiate upon them. Such is a great part of the magnificent study 

 upon which we have touched in our preceding lectures. Space, irnmensity, 

 infinity, pure incorporeal intelligence, matter created out of nothing, innu- 

 merable systems of worlds, and innumerable orders of beings ; — where is the 

 mind strong enough to grapple with such ideas as these ? They at once en- 

 tice and overwhelm us. Reason copes with them till she is exhausted, and 

 then gives us over to conjecture. Hence, as we have already seen, inven- 

 tion at times takes the place of induction, and the man of wisdom has his 

 dream as well as the man of fancy. 



Let us descend from such magnificent flights : let us quit the possible for the 

 actual; and equally incapable of following up the fugitive material of which 

 the visible universe consists, into its elementary principles and collective mass, 

 let us examine it as far as we are able, in the general laws, structure, and 

 phenomena it exhibits in the solid substance of the globe on which we tread. 



It is this inquiry that constitutes the science of geology, a brief outline of 

 which is intended as a study for the present lecture ; — a science than which 

 few are of more importance, but which is only at present in its infancy, and 

 of course almost entirely indebted for its existence to the unwearied assiduity 

 and discoveries of modern times. 



The direct object of geology is, to unfold the solid substance of the earth 

 —to discover by what causes its several parts have been either arranged or 

 disorganized— and from what operations have originated the general stratifi- 

 cation of its materials, the inequalities of its surface, and the vast variety of 

 bodies that enter into its make. 



In pursuing this investigation, many diflficulties occur to us. The bare 

 surface, or mere crust of the earth's structure, is the whole we are capable of 

 boring into, or of acquiring a knowledge of, even by the deepest clefts of vol- 

 canoes, or the deepest bottoms of different seas. It is not often, however, 

 that we have the power of examining either seas or volcanoes so low as to 

 their bottom. The inhabitable part of the globe bears but a small proportion 



