X PREFACE. 



The phenomena of nature are ever before us, and their 

 variety is without limit. One, therefore, who has 

 pursued the study of nature throughout his course of 

 education will never be at a loss for fresh material for 

 observation. Especially is this true of that science to 

 which the pupil is introduced in the present work. 



The only other consideration which I shall present 

 is the moral effect of the early study of natural science. 

 Ever varying views of the traces of the wisdom, power, 

 and goodness of the Deity can not fail to lodge in the 

 young mind sentiments and opinions, which will be 

 apt to forestall successfully the arguments of skep- 

 ticism that may be presented in after years. No 

 mere general views can do this, though they are often 

 relied upon; but the actual and definite knowledge 

 which study and observation give is required to effect 

 it. This benefit can hardly be overestimated. The 

 preoccupation of the mind by clear and abundant evi- 

 dence is a preventive measure of vast importance. 

 Better is it thus to shut out error, than to permit its 

 admission and then attempt to cast it out. 



The author has in the course of preparation books 

 on some of the other natural sciences Natural Philos- 

 ophy, Chemistry, etc. having the same general plan 

 which has been adopted in this work. His object is 

 to aid in the introduction of these studies into the 

 common school, as well as the academy and college. 



The books* which I have already prepared have 

 been used in some schools as reading-books at the 

 same time that they are used for study, and with 

 marked success. The plan adopted is this. The 

 class read the lesson, the teacher remarking upon it 

 so far as is thought proper ; and then the recitation is 



