PREFACE. 



The Microscope and its applications in tbe Arts, and in general science, 

 having deservedly occupied a prominent place in the pages of THE TECH- 

 NOLOGIST, OR INDUSTRIAL MONTHLY, a very large number of enquiries in 

 regard to the best methods of using and applying this useful instrument 

 have been directed to us. It would have been easy to answer these en- 

 quiries by a reference to some one of the many treatises that have been 

 published on this subject, but as most of these works are expensive, and 

 as many of our correspondents desire an aivs^?r in a more concise and 

 simple shape, we have endeavored to give, in cheap and compact form, the 

 information that is most usually demanded. 



It is an unfortunate fact that while the microscope is daily growing in 

 favor with those who know anything of its achievements, the operations 

 of certain parties, too weh" known to the public, have brought a certain 

 degree of suspicion upon all attempts to popularize this most valuable 

 instrument. Microscopes, varying in price from twenty-five cents to two 

 dollars and a half have been offered for sale, and the claim made for them 

 that they are capable of showing clearly the structure of the more min- 

 ute tissues, and that they may be used to advantage by physicians and 

 naturalists. To the young student whose means are limited, and to the 

 country practitioner, whose ability to supply himself with needed books 

 and instruments often falls far short of his desires, the offer of a service- 

 able microscope for a couple of dollars is a great temptation, and when 

 the instrument in question is endorsed by a long list of clergymen, law- 

 yers, and even editors, this temptation becomes irresistible. And if the 

 purchaser should happen to be unfamiliar with really good microscopes, 

 and unable to discriminate between a clear and accurately defined view 

 of any object and one that is distorted and incorrect, he may be led to use 

 it, and so fall into the most serious mistakes. That this, unfortunately, 

 does happen too often must be well known to all who are familiar with the 

 subject, and it is within our own knowledge that the most worthless cari- 



