x PREFACE. 



successive stages, equal in interest if unequal in magnitude : 

 the Greek, the Arabian, the Mediaeval, the Revival, and 

 the Modern. This, then, is a modest survey of science, 

 with its origin, growth, and results, and is addressed to the 

 student and the general reader. 



And as scientific history rather than science itself is the 

 main object in view here, the majority of the facts recorded 

 are merely stated and enumerated, without those explanatory 

 details which would be indispensable in a didactic work ; 

 yet, now and then, the statement has been enlarged upon 

 so as to enable the reader to perceive the importance, the 

 bearings, and the consequences of a scientific fact. This 

 occurs especially in the sketch of the Modern period, for 

 the Author felt that if he confined himself to the simple 

 definition of a law, or the mere enumeration of discoveries, 

 the reader would probably fail to draw right inferences or 

 apprehend the full significance of the case. Besides, more 

 interest is naturally attached by readers to a recent dis- 

 covery which they have witnessed, so to speak, and about 

 which the whole world may be ringing, than to an older 

 one. They see the railway engine, the telegraph, the electric 

 light, and they welcome an explanation which, exempt from 

 technicalities, enables them to understand the cause of their 

 power. They have heard of the spectroscope, and naturally 

 again they will welcome a brief description which makes 

 plain to them the beauty of its principles, the range of its 

 effects, and the extent of the benefits it bestows. The 

 meagreness of details, consistent with the limited plan of 

 the book and prevalent in some portions of it, has then 

 occasionally been abandoned, and replaced by comparative 



