

EDITORS' PREFACE. 



OTWiTHSTANDiNG the large number of scientific 

 works which have been published within the last few 

 years, it is very generally acknowledged by those who 

 are practically engaged in Education, whether as 

 Teachers or as Examiners, that there is still a want of 

 Books adapted for school purposes upon several 

 important branches of Science. The present SERIES 

 will aim at supplying this deficiency. The works 

 comprised in the SERIES will all be composed with 

 special reference to their use in school- teach ing ; 

 but, at the same time, particular attention will be 

 given to making the information contained in them 

 trustworthy and accurate, and to presenting it in 

 such a way that it may serve as a basis for more 

 advanced study. 



In conformity with the special object of the Series, 

 the attempt will be made in all cases to bring out the 

 educational value which properly belongs to the study 

 of any branch of Science, by not merely treating of its 



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