54> Things not generally K 



nown. 



THE GREAT TRUTHS OF ASTRONOMY. 



THE difficulty of understanding these marvellous truths has 

 been glanced at by an old divine (see Things not generally 

 Known, p. 1) ; but the rarity of their full comprehension by 

 those unskilled in mathematical science is more powerfully 

 urged by Lord Brougham in these cogent terms : 



Satisfying himself of the laws which regulate the mutual actions of 

 the planetary bodies, the mathematician can convince himself of a truth 

 yet more sublime than Newton's discovery of gravitation, though flow- 

 ing from it ; and must yield his assent to the marvellous position, that 

 all the irregularities occasioned in the system of the universe by the 

 mutual attraction of its members are periodical, and subject to an eter- 

 nal law, which prevents them from ever exceeding a stated amount, and 

 secures through all time the balanced structure of a universe composed 

 of bodies whose mighty bulk and prodigious swiftness of motion mock 

 the utmost efforts of the human imagination. All these truths are to 

 the skilful mathematician as thoroughly known, and their evidence is as 

 clear, as the simplest proposition of arithmetic to common understand- 

 ings. But how few are those who thus know and comprehend them ! 

 Of all the millions that thoroughly believe these truths, certainly not a 

 thousand individuals are capable of foil owing even any considerable por- 

 tion of the demonstrations upon which they rest ; and probably not a 

 hundred now living have ever gone through the whole steps of these 

 demonstrations. Dissertations on Subjects of Science connected with 

 Natural Theology, vol. ii. 



Sir David Brewster thus impressively illustrates the same 

 subject : 



Minds fitted and prepared for this species of inquiry are capable of 

 appreciating the great variety of evidence by which the truths of the 

 planetary system are established ; but thousands of individuals, and 

 many who are highly distinguished in other branches of knowledge, are 

 incapable of understanding such researches, and view with a sceptical 

 eye the great and irrefragable truths of astronomy. 



That the sun is stationary in the centre of our system ; that the earth 

 moves round the sun, and round its own axis ; that the diameter of 

 the earth is 8000 miles, and that of the sun one hundred and ten times 

 as great; that the earth's orbit is 190,000,000 of miles in breadth ; and 

 that if this immense space were filled with light, it would appear only 

 like a luminous point at the nearest fixed star, are positions absolutely 

 unintelligible and incredible to all who have not carefully studied the 

 subject. To millions of our species, then, the great Book of Nature is 

 absolutely sealed ; though it is in the power of all to unfold its pages, and 

 to peruse those glowing passages which proclaim the power and wisdom 

 of its Author. 



