PREFACE 



A microscope, like any other instrument of precision, 

 cannot be made to do its best work without some 

 knowledge on the part of the user as to .how to keep 

 it in perfect condition, and an intelligent understanding 

 of its parts, their use and relations. 



The purpose of this little book is to bring before you 

 some practical helps in clear concise form, which will 

 enable you to obtain the best possible results when work- 

 ing with the microscope. 



We make no attempt to go into the optical principles 

 involved in the microscope except in so far as it is neces- 

 sary to direct in its use. For these we refer you to more 

 pretentious works, The Microscope, by Dr. S.H. Gage; 

 The Microscope and its Revelations, by Carpenter & 

 Dallinger. 



Let it be remembered that no amount of direction will 

 take the place of good judgment and careful painstaking 

 effort on your part, and that it is only the perfect ad- 

 justment of every part in relation to every other part 

 which brings the best results. The neglect of one detail 

 may destroy the virtues of all the others. 



It is with a desire to help and a hope that your work 

 with the microscope may prove pleasant and profitable 

 that we present this little volume. 



SPENCER LENS CO. 



266119 



