ASTRONOMY. 



83 



tffirms, that he haa discovered mountains on the 

 surface of this globe, one of which is 10, another 

 11, and a third 22 miles high. It appears also 

 to be encompassed with an atmosphere, the 

 densest part of which is about 16,000 feet high. 

 About twice in the course of a century, this pla 

 net appears to pass, like a dark spot, across the 

 sun s disk. This is termed the transit ot Venus. 

 The last transit happened June 3, 1769 ; the 

 next will happen on December 8, 1874, which 

 will be invisible in Europe. Another will hap 

 pen on the 6th of December, 1882, which will be 

 partly visible in Great Britain. 



The Earth is the next planet in the system. 

 Ii moves round the sun in 365 days, 5 hours, and 

 49 minutes, at the distance of 95 millions of 

 miles, and round its axis in 23 hours, 56 minutes, 

 4 seconds. The former is called its annual, and 

 the latter, its diurnal motion. That the earth 

 is, in reality, a moving body, is a fact which can 

 no longer be called in question ; it is indeed sus 

 ceptible of the clearest demonstration. But my 

 limits will not permit to enter into a detail of the 

 arguments by which it is suppprted. I have al 

 ready adverted to one consideration, from which 

 its diurnal rotation may be inferred. (See p. 

 23.) Either the earth moves round its axis 

 every day, or the whole universe moves round it 

 in the same time. To suppose the latter case to 

 be the fact, would involve a reflection on the 

 wisdom of its almighty Author, and would form 

 the only exception that we know to that beauti 

 ful proportion, harmony, and simplicity, which 

 appear in all the works of nature. Were it pos 

 sible to construct a machine as large as the city 

 of London, and to apply to it mechanical powers 

 sufficient to make it revolve on an axis, so as to 

 carry round a furnace for the purpose of roasting 

 a joint of mutton, suspended in the centre of its 

 motion while we might admire the ingenuity 

 and the energies displayed in its construction 

 all mankind would unite in condemning it as a 

 display of consummate folly. But such an extra 

 vagant piece of machinery would not be half so 



20 degrees, in 24 hours, 34 minutes, determined the 

 time of its rotation to be 23 hours and 20 minutes. 

 On the other hand, Bianchini, from similar observa 

 tions, concluded, that its diurnal period was 24 days 

 and 8 hours. The difficulty of deciding between 

 these two opinions, arises from the short time in 

 which observations can be made on this planet, either 

 before sun-rise or after sun-set, which prevents us 

 from tracing, with accuracy, the progressive motion 

 of its spots for a sufficient length of time. And al 

 though an observer should mark the position of the 

 spots, at the same hour, on two succeeding evenings, 

 and find they had moved forward about 20 decrees 

 1n 24 hours, he would still be at a loss to determine, 

 wu^her they had moved 20 degrees in all, since the 

 prece &quot;ig observation, or had finished a revolution, 

 and 20 decrees more. In &quot; Nicholson s Philosophical 

 Journal,&quot; vol. 38. I endeavoured to show how this 

 point maybe determined by observations on Venus 

 in the day-time, by which, in certain cases, the pro 

 gressive motion of her spots might be traced, without 

 Interruption, for 12 hours or more, which would 

 completely settle the period of rotation. 

 38 



preposterous as to suppose, that the vast universe 

 is daily revolving around our little globe, and that 

 all the planetary motions have an immediate re 

 spect to it. And shall we dare to ascribe to him 

 who is &quot; the only wise God,&quot; contrivances 

 which we would pronounce to be the perfection 

 of folly in mankind ? It is recorded of the astro 

 nomer Alphonsus, king of Castile, who lived in 

 the 13th century, that, after having studied the 

 Ptolemaic system, which supposes the earth at 

 rest in the centre of the universe, he uttered the 

 following impious sentence : &quot; If I had been of 

 God s privy council, when he made the world, I 

 would have advised him better.&quot; So that false 

 conceptions of the system of nature, lead to erro 

 neous notions of that adorable Being who is pos 

 sessed of infinite perfection. We find that bodies 

 much larger than the earth have a similar rota 

 tion. The planet Jupiter, a globe 295,000 miles 

 in circumference, moves round his axis in less 

 than ten hours ; and all the other planetary 

 bodies, on which spots have been discovered, are 

 found to have a diurnal motion. Besides, it is 

 found to be a universal law of nature that smaller 

 globes revolve round larger ; but there is no ex 

 ample in the universe, of a larger body revolving 

 around a smaller. The moon revolves around 

 the earth, but she is much smaller than the 

 earth; the moons which move around Jupiter, 

 Saturn, and Herschel, are all less than their pri 

 maries, and the planets which perform their re 

 volutions around the sun are much less than that 

 central luminary. 



With regard to the annual revolution of the 

 earth, if such a motion did exist, the planetary 

 system would present a scene of inextricable con 

 fusion. The planets would sometimes move 

 backwards, sometimes forwards, and at other 

 times remain stationary; and would describe 

 looped curves, so anomalous and confused, thai 

 no man in his senses could view the all-wise 

 Creator as the author of so much confusion. 

 But, by considering the earth as revolving in an 

 orbit between Venus and Mars, (which all ce 

 lestial observa ions completely demonstrate,) all 

 the apparent irregularities of the planetary mo 

 tions are completely solved and accounted for ; 

 and the solar system presents a scene of beauty, 

 harmony and grandeur, combined with a simplicity 

 of design which characterizes all the works of 

 Omnipotence. 



The Moon. Next to the sun, the moon is to 

 us the most interesting of all the celestial orbs. 

 She is the constant attendant of the earth, and 

 revolves around it in 27 days, 8 hours ; but the 

 period from one new or full moon to another is 

 about 29 days, 12 hours. She is the nearest of 

 all the heavenly bodies ; being only about two 

 hundred and forty thousand miles distant from the 

 earth. She is much smaller than the earth ; be 

 ing only 2,180 miles in diameter. Her surface, 

 when viewed with a telescope, presents an into 



