510 
POPULAR SCIENCE REVIEW. 
Neither need the author regret the pains which he has taken to prepare 
the “ survey ” with the utmost accuracy, for he has rendered it a most 
valuable work of reference for students, in whose minds it will clear up 
many doubts. 
For example, if a tyro were to take up two of the works already referred 
to, which do not pretend to treat of ancient astronomy, he would find in 
both of them that the Pythagorean and Copernican systems of the universe 
are regarded as identical, or nearly so, each having the sun for its centre. 
The uninitiated student would be puzzled to find these two systems 
confounded, for it is generally understood that there was a great differ- 
ence between the theories of the two astronomers who were 2,000 years 
removed from each other. 
A reference to Sir George Lewis’s book will, however, explain the dif- 
ference between the two theories : — 
The Pythagoreans believed that the earth and the heavenly bodies, 
including the sun, revolved around a “ central fire,” a body of which they 
had but a vague conception ; whilst Copernicus placed the sun in the 
centre, and thus propounded the true solar theory. Pythagoras and his 
school may be compared to the man who, after a life-long effort, catches 
a glimpse of some new theory, or constructs the model of some valuable 
machine, which is rendered useless by its imperfection; whilst Copernicus 
resembles some gifted successor, who, having had the benefit of his ances- 
tor’s experience, coupled with that of intervening ages, sets his mind to 
work, and completely solves the problem, propounded and in part unfolded 
by his predecessor. 
Of Sir George Lewis’s book we are compelled also to say that it can 
hardly be termed “ popular but it will be found interesting to all 
students of the science, and will be largely employed in educational 
establishments. 
The second portion of the volume is devoted to chronology, and has 
given rise to a controversy on “ Egyptology on the construction of the 
records left by the Egyptians concerning the history of our race. It has 
nothing to do with the subject of astronomy, however interesting it may 
be, and ought to have been more clearly separated from the first portion of 
the work ; for as it stands at present the reader is led to expect a return 
to the original subject, an expectation in which he is doomed to disap- 
pointment. We have said enough to show how highly we value this 
instructive work, and recommend it to the perusal of all who are interested 
in the history of astronomy in past ages. 
