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PRACTICAL AND SPECULATIVE GEOLOGY. 



Let us then endeavour to ascertain by vvliat means we may be- 

 come acquainted with the structure of the solid covering of our globcc 

 Were these means bounded by the power of man to penetrate be- 

 low the surface, our knowledge must ever remain very limited and 

 imperfect ; but natural operations have greatly facilitated our inqui- 

 ries, and have broken the rocky pavement of the globe, and raised 

 up or laid bare the mineral substances of which it is composed. By 

 an attentive examination of the situations where the rocks and strata 

 are thus exposed to our research, we lay the foundation of the science 

 denominated Geology. 



Geology is derived from two Greek words, ge " the earth," and 

 logos " reason," and signifies the Science of the Earth. Werner 

 and his disciples, and also some of the French geologists, have chan- 

 ged the term mio geognosy ; but for this change no sufficient reason 

 can be assigned, and it is contrary to established analogies of lan- 

 guage.* Philosophers, in former ages, neglected the examination 

 of the earth, and contented themselves with vain speculations respec- 

 ting its formation ; whereas the only proper answer to the question. 

 How was the ivorJd made ? is briefly this — " By the almighty power 

 of its Creator." We may however be permitted, and indeed we are 

 almost irresistibly impelled, to inquire into the nature of the secondary 

 causes, that have been operative in reducing the surface of our globe to 

 its present state. This inquiry comprises what may properly be de^ 

 nominated Speculative Geology. Nor is this, as some assert, entirely 

 useless: the advocates of particular systems have engaged in an 

 active examination of nature to support their opinions, and have 

 "compassed sea and land to gain proselytes:" thus numerous facts 

 have been discovered, with which we should not have been acquaint- 

 ed had they remained idle in their studies. 



The earth is now well known to be one of those globular, bodies 

 called planets, that revolve round the sun in orbits nearly circular,, 

 and in stated periods of time, which bear a certain ratio to their re- 

 spective distances from it. They turn round their axis with differ- 

 ent degrees of velocity; and this motion appears to have had con- 

 siderable influence on their external shape, by enlarging their equa- 

 torial diameters ; they are not perfect spheres, but are more or less 

 flattened at their poles. 



In the planet Jupiter, the velocity of the equatorial parts is more 

 than four hundred miles per minute, whilst in the same time the equa- 

 torial parts of the Earth have moved only seventeen miles. A dif- 

 ference between the polar and equatorial diameter of Jupiter is per- 

 ceptible with a telescope that has a distinct magnifying power of a 

 hundred times, and it is ascertained to be as 12 to 13. The eqiia- 



* Nothing can be more unmeaning than the apologies that have been offered for 

 substituting {gnosis) "knowledge," for {logos) "reason." By the same rule we 

 ought to change meteorology, physiology, &c. into metcorognosy, physiognosy, &c.. 



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