340 Mr. Nixon on a Repeating Circle, by ivhich any Multiple 



without creating greater difficulties than it tends to explain? 

 If so, surely it ought to be discarded from the science of geo- 

 logy, although no other hypothesis may be substituted for it. 



Geologists have sometimes carried their speculations so far 

 as to refer the spheroidal form of the earth to its having once 

 been a mass of plastic matter in igneous fusion or aqueous so- 

 lution, its pi'esent shape beuig due simply to the operation of 

 mechanical principles. But these appeal" rather to militate 

 against the assumption, because the rocks, instead of being 

 parallel to the ecjuator, have their prevailing stratification at 

 considerable angles to it in various parts of the world : more- 

 over, the proportion of land to the water between the tropics 

 exceeds that which is near the poles, and the specific gravity 

 of the rocks is equally great; whereas, on mere mechanical 

 principles, the most fluid and lightest matter ought to accu- 

 mulate near the equatoi', and the heaviest near the poles. 



If their arguments be founded on the adaptation of the 

 earth's form to the rate of its daily revolution, — in which of 

 the works of the great Creator is there not the most perfect 

 and wonderful adaptation to the end designed? And if it can- 

 not be denied that in the beginning it existed in things the most 

 minute, I see no ground for imagining that this great globe, 

 with which the existence of animal and vegetable life is so in- 

 dispensably connected, should present a solitary exception. 



Many of the operations in nature, and the laws which re- 

 gulate them, may, to a certain extent, be comprehended by 

 man; and the more they become developed, the more beauti- 

 ful and harmonious they appear: but we cannot find laws to 

 apply to the original organization of the earth, or the things 

 which it contains. 



The distinction is important in every point of view ; and it 

 is surely more useful and instructive to accumulate facts and 

 observations upon the actual state of things and their mutual 

 relations, and to deduce from them such conclusions as expe- 

 rience and analogy may justify, than to hazard conjectures, 

 and puzzle ourselves about questions which probably are, and 

 ever will be, out of our reach. 



LXIII. Description of a Repeati7ig Circle, by 'which any Mul- 

 tiple of an Altitude may be measured from one Observation 

 by the Telescope. By John Nixon, Esq.* 



SEVERAL years ago the late Mr, James Allan constructed 

 for me a repeating circle, designed originally for the mea- 

 surement of (oblique) terrestrial angles, which, when mounted 



* Communicated by the Author. 



