PKEFACE TO THE TENTH EDITION. 



WENTY- EIGHT TEARS have passed 

 away since the first edition of this book 

 on the microscope was published. It was 

 hailed as the pioneer of a more useful 

 form of literature than had heretofore 

 appeared on the history, construction and appli- 

 cation of the instrument. In this period of time, 

 nine large editions, exceeding in the aggregate 60,000 

 copies, have been sold out, and yet another edition is 

 called for a proof, if it were wanting, that the book 

 has not only maintained its ground, but its popularity. 



In issuing a tenth edition, the Author, by a careful 

 revision of the text, and by an addition of no fewer 

 than fifty new woodcuts, trusts that his book has been 

 made more acceptable and useful to those for whom 

 it was originally intended. Part I. has been almost 

 wholly rewritten and rearranged. To Mr. Frank 

 Crisp the Author is indebted for Professor Abbe's 

 theory of microscopic vision. To the processes of 

 hardening, section-cutting and staining much in vogue> 

 and which have created a new era in physiological 

 studies, have been assigned the space they seem to 

 merit. Part II. has been carefully revised ; a chapter 

 added on the application of the microscope to minera- 

 logical and spectroscopical analysis, and the examina- 

 tion of potable water. That his book may for some 

 years to come be found a familiar introduction to the 

 use of the microscope, and the study of microscopical 

 science, is the earnest wish of the Author. 



1, BEDFORD SQUARE, June, 1882. 



