INTRODUCTION. IX 



The ponds - referred to are all either close to, 

 or within a moderate distance of, London; hut 

 similar objects will in all probability be obtained 

 from any ponds similarly situated, and the des- 

 criptions and directions given for the capture of 

 the minute prey will be found generally applicable. 

 Care has been taken throughout to explain the 

 most convenient methods of examining the objects, 

 and although verbal descriptions are poor substitutes 

 for the teachings of experience, it is hoped that 

 those here given will remove some difficulties from 

 a pursuit that no intelligent person can enter upon 

 without pleasure, or consent to abandon when its 

 elementary difficulties have been mastered, and the 

 boundless fields of discovery are opened to view. 

 Let not the novice be startled at the word 

 "discovery." It is true that few are likely to 

 arrive at new principles or facts which will inscribe 

 their names upon the roll of fame; but no one 

 of ordinary powers can look at living objects 

 with any considerable perseverance, without seeing 

 much that has never been recorded, and which is 

 nevertheless worthy of note; and Avhen the mind, 

 by its own exertions, first arrives at a knowledge 

 of new truth, an emotion is felt akin to that 

 which more than recompenses the profoundest 

 philosopher for all his toil. 



