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XIX. Notices respecting New Books. 



Elementary Lessons in Astronomy. By J.NormanLockyeRjF.-K.AS'. 

 London and Cambridge : Macmillan and Co. 



r 2^HE schools of our country are much indebted to the author of 

 -*- this little work both for the substance and the shape of the in- 

 formation which he has given them. 



The amount of thought which he has bestowed upon the arrange- 

 ment of his materials has not been thrown away, but has produced 

 a work which will give the young student (as well as children of a 

 larger growth) a clear and more complete idea of that great whole 

 called the universe than most works of greater pretensions. 



The custom hitherto has been for writers on astronomy to direct 

 their readers' attention rather to the instruments by which observa- 

 tions are made, and to the principles according to which they are 

 discussed, than to invite them to begin by taking a bird's-eye view 

 of the Cosmos. We are told how to adjust a transit, and how to 

 measure the sun's distance from the earth ; but our energies are so 

 much used up in understanding these things, that we have little 

 strength left to contemplate as a whole the grand reality which they 

 disclose. 



But our author adopts a different method, and beginning with 

 what we see, and first of all with the stars, we have a series of les- 

 sons in which the reader has clearly put before him a view of the 

 magnitudes and distances of these bodies, as well as an account of 

 their occasional peculiarities, such as colour and variability. In the 

 nebular hypothesis, which is then described, we receive a hint of the 

 process by which matter has been wrought from the state of pri- 

 meval chaos into a sun or star. 



When the reader has by this means become properly impressed 

 with the magnitudes with which we deal in astronomy, one particular 

 star is singled out for especial consideration. Our own star or sun 

 is that one of all the host of heaven with which we are most inti- 

 mately acquainted. His appearance and habits are therefore de- 

 scribed, and we receive an insight into his chemical constitution. 



Still proceeding downwards from greater to lesser magnitudes, we 

 are next invited to consider the minor bodies of the solar system ; 

 and just as the sun was singled out as the type of the stars, so the 

 earth is singled out as the type of the planets. Astronomers have 

 been fond of drawing attention to the adaptation implied in the 

 fact that the gravitating centres of the various systems are also 

 the centres of light and heat ; but it is only of late years that 

 we have come to recognize that both these facts can be explained 

 by the operation in two different w r ays of one and the same law. 

 Accordingly we have another definition of planets, and one to which 

 the author has given considerable prominence, namely that planets 

 are cold while suns are hot, just as truly as that they are wandering 

 while suns are fixed. 



