EARTH. 



the avarice of man, had led him to pene- 

 trate as far as his limited powers will per- 

 mit towards the centre, he had but few op- 

 portunities of ascertaining, and that only 

 from analogy, how the different strata of 

 the earth was disposed, and connected or 

 held together by the vast masses of stone, 

 which may be called the bones of this vast 

 body. As scientific men were gradually 

 admitted to the knowledge of the secrets 

 of the earth by the exertions of the mi- 

 ner, in the same proportion did all ideas 

 of a chaos vanish, and we are now con- 

 vinced, though their excavations are mere 

 punctures in the globe, that, were it pos- 

 sible to penetrate through, it would tend 

 to prove that self-existing causes, origi- 

 nating immediately from the Creator, are 

 constantly employed in preserving the 

 whole from derangement, and what \ve 

 term decay, which, in truth, is simply a 

 change of form, and not annihilation. 

 The celebrated miner, Agricola, was the 

 first who recorded the internal properties 

 of the earth, between whose time and 

 that of Werner some discoveries were 

 made as to its structure ; Lehman formed 

 the idea of primitive and secondary clas- 

 ses of mountains. Cronslad conjectured 

 the age of several mineral repositories. 

 Hamilton, Dolomieu, and Spallan/ani, 

 have gone to very successful and satisfac- 

 tory lengths in ascertaining the opera- 

 tions of volcanos, the nature of the ma- 

 terials which support them, and the sub- 

 stances they eject. Saussure has increased 

 our knowledge of rocks, Williams of the 

 independent formation of coal, and Wer- 

 ner has profited by every preceding ob- 

 servation, and, possessing a cultivated 

 genius of his own, united them into a 

 system which approaches nearer to the 

 truth than the nature of the subject would 

 lead us to suspect. Unfortunately, the la- 

 bour and expense of penetrating to any 

 great depth into the earth ever has, and 

 ever must, limit our knowledge of the ex- 

 tent of strata, and its similarity in differ- 

 ent latitudes ; but from the opportunities 

 already afforded by mines, we are led to 

 conclude that those lines of matter spread 

 through vast spaces, if not throughout the 

 globe ; many theories have been attempt- 

 ed, to account for their varieties and ca- 

 pricious elevations and depressions from 

 a horizontal direction. Dr. Woodward, 

 who deeply considered the subject, 

 supposes all the terrestrial masses dis- 

 posed in strata to have been dissolved by 

 the waters of the deluge, which subsiding, 

 the most ponderous fell to the bottom, 

 and the rest settled in gradations suited 



to their specific weights. This solution 

 naturally disposes the strata uniformly 

 horizontal, and he accounts for the breaks 

 in the lines and fissures every where ob- 

 servable, by the action of volcanos, earth- 

 quakes, &c. &.c. Buffbn's fancies of cor- 

 ners torn from the sun by comets, and 

 the earth liguificd by fire, barely deserve 

 notice, and make a disgraceful contrast 

 with Woodward's ingenious conjectures. 

 The surface of the earth is known by 

 every enlightened person to be compos- 

 ed of a confused mass of vegetable, and, 

 in some slight degree, of animal sub- 

 stances, below which, Jameson says, 

 there are four different kinds of struc- 

 ture : " The first is that which is to be 

 observed in hand specimens; it is the 

 smallest kind of structure, and occurs in 

 what are termed mountain-rocks or 

 stones. The second kind of structure, 

 or that of mountain-masses, is more on 

 the great scale, and is not to be observed 

 in hand specimens, but only in single 

 masses of rock. To this structure be- 

 longs stratification, and the seams of dis- 

 tinct concretions. The third kind of 

 structure is that of rock formations, or 

 those great masses of which the crust of 

 the earth is composed. To examine this 

 kind of structure, we must traverse con- 

 siderable tracts of country. The fourth 

 kind of structure is that of the earth it- 

 self, which is formed by the junction of 

 various formations. To examine this 

 structure, \ve must travel through many 

 countries." 



When in passing through long tracts of 

 land, we observe loose rocks, firm rocks, 

 clay, sand, tc. &.c. in succession, in those 

 instances the strata of the earth lay al- 

 most perpendicular, in large masses of 

 rocks, which present nearly a plain front, 

 the inclination of the strata is distinctly 

 risible, and in some cases their agree- 

 ment with others opposed to them de- 

 monstrate that they h^ve been separated 

 by some convulsion of the earth. 



The gravity of a portion of the earth 

 was calculated by Dr. Maskelyne in the 

 years 1774 and 1775, at the mountain 

 Schehallien, and its attraction on a plum- 

 met ascertained on each side ; besides 

 which, he computed the quantity of mat- 

 ter contained in it by a considerable num- 

 ber of sections in various directions ; and 

 the result being afterwards compared 

 with the acknowledged magnitude and 

 attraction of the earth, he found thai the 

 density was as 9 to 5 of common stone, 

 and as 9 to 2 water; whence it vas in- 

 ferred that large quantities of mcl lay 



