PREFACE TO THIRD EDITION. 



The past demand for this little volume makes 

 extended remarks superfluous, the new edition 

 appearing as evidence that it is considered of some 

 value. 



This edition has been almost entirely rewritten 

 to bring it in accord with the advance which has 

 been made in the construction of microscopes and 

 accessories and while it is not expected to be a 

 complete guide, it is, nevertheless, hoped that it 

 will make the labor of the beginner more easy. 



Since its first issue there have appeared two 

 books covering the same purpose: " The Micro- 

 scope and Microscopical Methods " by Prof. S. H. 

 Gage of Cornell University and " Microscopical 

 Praxis " or " Simple Methods of Ascertaining the 

 Properties of Microscopical Accessories " by Dr. 

 A. C. vStokes, both of which are heartily commended 

 to the microscopist. Neither should be wanting- in 

 a microscopical library. The writer is also pleased 

 to acknowledge the suggestions of an enlarged 

 scope for this book, which he has obtained by a 

 perusal of them, as well as from the admirable 

 work of Dr. W. H. Dallinger in the latest issue of 

 Carpenter, "The Microscope and Its Revelations" 



