Vlll 



PREFACE. 



Indulgent readers, though they muft perceive er- 

 rors and imperfedions, will naturally make fome al- 

 lowance for the variety of refearch, and the labour of 

 condenfing fo much matter into fo fmall a compafs. 

 He is a bad author, it has been faid, who affords nei- 

 ther an aphorifm nor a motto. 



I cannot refrain from mentioning a circumftance 

 which has often made me uneafy. The expedlations 

 of fome friends were higher than I was confcious my 

 abilities could reach. 



Upon the whole, the general defign of this publi- 

 cation is, to convey to the minds of youth, and of 

 fuch as may have paid little attention to the ftudy of 

 Nature, a fpecies of knowledge which it is not diffi- 

 cult to acquire. This knovv'ledge will be a perpetual 

 and inexhauilible fource of manly pleafures ; it will 

 afford innocent and virtuous amufemcnt, and will oc- 

 cupy agreeably the leifure or vacant hours of life. 



CON- 



