LESSONS IN ASTRONOMY. 



17 



LESSONS IN ASTRONOMY. I. 



OBJECTS AND EARLY HISTORY OF THK 8CIKNCE EARLY 

 A8TKONOMEKH; THALE8, II 1 1 TA l:< HUB, PTOLEMY. 



OK all the sciences which arrest the attention and engage the 

 thought t m uikind, the science of astronomy is assuredly one 

 of tin- grandest, most ennobling, and most sublime. Others, 

 though they tend greatly to expand and eurich'.tiu; mind, chain 

 it down to the earth; but thin lifts it up, and curries it away 

 tar li.'vond the boundaries of the finite, till it is almost lost in 

 Miu illimitable void of space. 



Astronomy seems to lift man out of himself, and to place him 

 on a standpoint far removed from the world ho inhabits, which 

 ices to a mere unit in the glorious whole; and aa he 

 beholds the uualtering regularity and unceasing motion of the 

 heavenly bodies by which ho is surrounded, and by slow degrees 

 comes to perceive that all their varying and apparently compli- 

 cated motions resolve themselves into the most beautiful 

 simplicity, and ore all governed by a few plain and simple laws, 

 he is led to see fresh proofs of the power and wisdom of Him 

 v/ho by His word called them into being, and launched them 

 forth in space. 



By this science the student learns the hard lesson that the 

 evidence of the senses is not always to bo depended on ; that the 

 apparently immovable earth is in reality in a state of continual 

 motion, both on its own axis and around the sun ; and that the 

 real movements of the heavenly bodies are quite different from 

 those which are apparent. He learns, too, that this world, which 

 he has always been accustomed to regard as the largest and 

 most important body in existence, is classed among the orbs of 

 i . and even among the smallest of them ; that it is, indeed, 

 but a speck in creation, quite invisible from the nearest of those 

 fixed stars which stud the sky ; and thus he is led to feel his own 

 insignificance. And yet when ho finds that the motions of all 

 these bodies can be accurately determined, that their sizes and 

 even their weights can be measured, that some of the elements 

 Tvhich enter into their composition can be told, and that their 

 distances can be ascertained, though so great that light, with all 

 its sp3ed, takes thousands of years to cross the chasm that 

 separates them from us, he sees something of the immense power 

 vrath wliich the human mind has been endowed. 



As he advances he finds that the sun and moon, which appear 

 like small bodies performing their journeys round the earth, are 

 in reality worlds, the former of them greatly exceeding in size 

 that on which he lives ; that the stars, which he has looked upon 

 as mere points in the sky, are in reality suns, with systems of their 

 own revolving around them the " centres of life and light to 

 myriads of unseen worlds ;" and that these suns, with their 

 attendant worlds, are all revolving in mighty orbits around one 

 common centre, and forming one grand cluster. 



The telescope still further extends his view, for by its powerful 

 aid he discovers here and there faint nebulce, or patches of cloudy 

 light, scattered among the stars ; and these at length resolve 

 themselves into complete clusters, similar to that which is made 

 up of our sun and all the other stars around us. But here the 

 power of his instrument fails him, and the distances and magni- 

 tude of these systems are such as to baffle all computation or 

 thought. Man can only stand on the verge of the infinite, and 

 wonder and adore the glories of Him who filleth all space. 



We must therefore come to the study of this science with a 

 tnind specially prepared for the reception of its truths, being 

 ready, on the one hand, to receive all truths which shall be 

 shown to be fully supported by careful observations and proof, 

 even though they appear to be sometimes almost contrary to the 

 evidence of the senses ; and, on the other hand, to dismiss all 

 those crude notions previously formed in the mind which, upon 

 consideration, are not found to be supported by facts, and which 

 tend, therefore, to hinder and mislead us in our inquiries. The 

 importance of this latter point will be clearly seen when wo 

 notice how, in the early ages of astronomy, all true progress was 

 effectually checked by the firm hold which certain preconceived 

 notions had acquired over the human mind ; and how, when at 

 last the fact of the earth's motion was discovered, and the com- 

 plicated and cumbrous systems previously believed in were thus 

 at one stroke swept away, persecution and opposition of every 

 kind were heaped upon the men whose intellect had thus solved 

 the difficulties of ages. 



The science of astronomy dates from an antiquity far more 

 80 N.E. 



remote than any other science, many important discoveries 



having been made in it at a period anterior to all written history. 



ic book of Job, which in usually admitted to be the rnont 



at book in the world, we find reference to Arctunw, Orion, 



ai..| tiiu i'luiados, showing that, even at this early period, name* 



hod been given to some of the constellations and stars. 



We can easily understand why this should be so. Every one 

 of us, when walking alone on a clear night, when the moon has 

 set, and the whole concave of heaven is studded with innumerable 

 stars, must have felt an anxious desire to know something of the 

 history and motions of those bodies. This desire was felt in the 

 early ages of the world, and in the East, where the science seems 

 to have had its origin, the settled weather, the clearness of th 

 air, and the cloudlessness of the sky, would all render these 

 observations more easy. In those early ages, too, men lived far 

 more in the open air than in the present day. Shepherds, for 

 instance, often watched with their flocks during the whole night, 

 and thus they would have frequent and favourable opportunities 

 for watching and noticing the movements of the stars. This 

 occupation, too, would serve well to beguile the otherwise tedious 

 hours of night, and we find accordingly that shepherds were the 

 first astronomers. 



Another reason why the science attracted so much attention . 

 was its great practical importance. Men soon noticed the 

 regular changes of the seasons. They would see that at one 

 time winter cold seemed to reign over all, and apparent death 

 held all the vegetable world. Spring then followed, with its 

 fresh leaves and opening flowers, and summer and autumn with 

 their fruits and stores of grain ; and they naturally inquired the 

 reason of all these changes. They would notice likewise that 

 during the summer months the sun was absent from them for 

 only a short time, and at noon attained a greater height above 

 the horizon than he did in the winter months, when the night 

 was long and the hours of daylight but few ; and they would 

 thus come to connect the changing seasons with the motions of 

 the sun, which were accordingly noted with greater accuracy. 

 In a similar way the changes of the moon, from the first narrow 

 crescent of light to the full round orb, and then back again, 

 would early be remarked. 



One other cause for the study of this science is found in man's 

 innate craving for the supernatural, or something beyond him- 

 self. The apparent immutability of the heavenly bodies, the 

 purity of their light, the regularity of their motions, and, above 

 all, the mystery which enveloped them, excited his admiration 

 and reverence ; and hence we find that they early became objects 

 of worship to the ignorant, and therefore superstitious, people of 

 that time. The study of their motions was therefore usually 

 pursued for some religious or astrological purpose, and the chief 

 astronomers were priests or professional diviners. 



We can easily understand why this was the case. It was seen 

 that the succession of the seasons and the alternations of day and 

 night were caused by the motions of the most important of the 

 heavenly bodies, and hence it was supposed that all the rest 

 exerted their influences over other matters that were going on 

 in the world, and that by the careful study of their motions and 

 changes future events in the history of men and nations might 

 easily be predicted. We find, accordingly, that astrologers were 

 consulted before any great or important work was undertaken, 

 and their advice was usually very strictly adhered to. 



The question as to what nations first cultivated this science 

 cannot be definitely settled. It seems probable, however, that 

 the earliest systematic observations of the stars were made by 

 the Chaldceans. 



The path of the sun among the fixed stare was very early 

 discovered, and these stars were arranged into the twelve con- 

 stellations, known as the signs of the zodiac, long before the 

 historical era. Many of the other constellations were also named, 

 but some were afterwards altered by the Greeks and Romans ; 

 and even in modern days a few additions have been made, as, for 

 instance, the Shield of Sobieski and the Heart of Charles L 



It must not be supposed that any resemblance can be traced 

 between the shape marked out by the stars and the figures they 

 are supposed to represent. The original idea seems to have 

 been merely to map out the sky into convenient portions for 

 examination, and at the same time to immortalise certain real 

 or mythical heroes ; but as the system became adopted uni- 

 versally, it has been retained to the present day, and server 

 ae a ready means of distinguishing and registering the stars. 



