THE CHRISTIAN PHILOSOPHER. 



producing colour, a second producing heat, and a 

 third chymical effects. Euler has computed that 

 the light of the sun is equal to 6500 candles at a 

 foot distance, while the moon would be as one 

 candle at 7| feet ; Venus at 421 feet ; and Jupi 

 ter at 1320 feet. That this immense luminary 

 appears so small to our eyes, is owing to its vast 

 distance, which is no less than ninety-five mil 

 lions of miles. Sooie faint idea of this distance 

 may be obtained, by considering, that a steam 

 boat, moving at the rate of 200 miles a day, 

 would require thirteen hundred years before it 

 could traverse the space which intervenes be 

 tween us and the sun. 



&quot;Hail sacred source of inexhausted light! 

 Prodigious instance of creating might . 

 His distance man s imagination foils ; 

 Numbers will scarce avail to count the miles. 

 As swift as thought he darts his radiance round 

 To distant worlds, his system s utmost bound.&quot; 



. Brown. 



The Planet Mercury . Mercury is the nearest 

 planet to the sun that has yet been discovered. 

 He is about 37 millions of miles distant from the 

 sun, and revolves around him in 88 days. His 

 diameter is about 3200 miles. Before the dis 

 covery of the four new planets, Ceres, Pallas, 

 Juno, and Vesta, in the beginning of the present 

 century, this globe was considered as the smallest 

 primary planet in the system. His surface, 

 however, contains above 32 millions of square 

 miles, which is not much less than all the habi 

 table parts of our globe. On account of his near 

 ness to the sun, he is seldom seen by the naked 

 eye ; being always near that quarter of the hea 

 vens where the sun appears ; and therefore, few 

 discoveries have been made on his surfac*, by 

 the telescope. M. Schroeter concludes, from 

 certain observations, that this planet revolves 

 round its axis in 24 hours and five minutes. The 

 sun will appear to an inhabitant of Mercury 

 seven times larger than to an inhabitant of the 

 earth ; and, if the degree of heat be in propor 

 tion to a planet s nearness to the sun, the heat 

 in this planet will be seven times greater than 

 on the surface of our globe ; and, consequently, 

 were the earth placed in the same position, all 

 the water on its surface would boil, and soon be 

 turned into vapour. Bjut the All-wise Creator 

 has, doubtless, attempered the surface of this 

 globe, and the constitution of the beings that 

 may occupy it, to the situation in which they 

 are placed.* 



From a variety of facts which have been observ 

 ed in relation to the production of caloric, it does not 

 appear probable, that the degree of heat on the sur 

 faces of the different planets is inversely propor 

 tional to the squares of their respective distances 

 from the sun. It is more probable, that it depends 

 chiefly on the distribution of the substance of caloric 

 on the surfaces and throughout the atmospheres of 

 these bodies in different quantities, according to the 

 different situations the v occupy in the solar system j 



Venus, the next planet in order from the .sun ; 

 revolves around him in 224 days, at the distance 

 of 68 millions of miles, and its diameter is about 

 seven thousand seven hundred miles, or nearly 

 the size of the earth ; and it turns round its axis 

 in the space of 23 hours and 20 minutes. This 

 planet is the most brilliant orb which appears in 

 our nocturnal heavens, and is usually distinguish 

 ed by the name of t .it morning and evening star. 

 When it approaches nearest to the earth, it is 

 about 27 millions of miles distant ; and at its 

 greatest distance, it is no less than 163 millions 

 of miles from the earth. Were the whole of 

 its enlightened surface turned towards the earth, 

 when it is nearest, it would exhibit a light and 

 brilliancy twenty-five times greater than it ge 

 nerally does, and appear like a small brilliant 

 moon ; but at that time, its dark hemisphere is 

 turned towards our globe. Both Venus and 

 Mercury, when viewed by a telescope, appear to 

 pass successively through all the shapes and ap 

 pearances of the moon ; sometimes assuming a 

 gibbous phase, and at other times the form of a half 

 moon, or that of a crescent ; which proves that 

 they are dark bodies in themselves, and derive 

 their light from the sun. The most distinct and 

 beautiful views of Venus, especially when she 

 appears as a crescent, are to be obtained in the 

 daytime, bv means of an equatorial telescope. 

 From a variety of observations which the author 

 has made with this instrument, it has been found 

 that Venus may be seen every clear day without 

 interruption, during a period of 583 days, with 

 the occasional exception of 13 days in one case, 

 and only 3 days in another a circumstance 

 which cannot be affirmed of any other celestial 

 body, the sun only excepted.f M. Schroeter 



and that these different quantities of caloric are put 

 into action by the influence of the solar rays, so as 

 to produce that degree of sensible heat requisite for 

 each respective planetary globe. On this hypothesis 

 which is corroborated by a very great variety of 

 facts and experiments there may be no more sen 

 sible heat felt on the surface of the planet Mercury, 

 than on the surface of Herschel, although one oi 

 these bodies is nearly 50 times nearer the sun than 

 the other. &quot;We have only to suppose that a small 

 quantity of caloric exists in Mercury, and a larger 

 quantity in Herschel, proportionate to his distance 

 from the centre of the system. On this ground, we 

 have no reason to believe, either that the planets 

 nearest the sun are parched with excessive heat, or 

 that those that are most distant are exposed to all the 

 rigours of insufferable cold, or that the different de 

 grees of temperature which may be found in these 

 bodies render them unfit for being the abodes of 

 sensitive and intellectual beings. 



t See Edin. Phil. Journ. No. V. July, 18-20, and No. 

 XIII. July 1822. I have found from observation, that 

 this planet may be seen in the day-time, when only 

 1 43 from the sun s centre ; and consequently 

 when its geocentric latitude at the time of the supe 

 rior conjunction exceeds that quantity, it may be 

 distinctly seen during the whole period of 583 days, 

 excepting about 35 hours before and after its inferior 

 conjunction. It is well known to astronomers, that 

 there has been a difference of opinion with respect 

 to the period of the rotation of this planet. Cassini, 

 from observations on a bright spot which advanced 



