INTRODUCTION. 



Thousands of microscopes throughout the country are at the pres- 

 ent day lying idle, simply because their owners do not know how to 

 use them. If properly employed they might be made to afford an 

 incalculable amount of instruction and amusement; but, as it is, they 

 are a drag upon the popularization of science, because they convey 

 the Idea that the microscope is a difficult instrument to use, and 

 that it is not of much account after we have learned to use it. The 

 owners of these microscopes have examined all the mounted objects 

 at their command, the entire number of which probably does not 

 exceed two or three dozen, and they have no information as to the 

 best methods of preparing common objects for examination or pre- 

 servation. Even the objects that they possess have never been ex- 

 plained to them, and are merely pretty toys. The fly's eye is inter- 

 esting because it looks like a piece of nettiug, and the butterfly's 

 wing is attractive because it is probably a little more brilliant than 

 the most brilliant silk dress, but neither of these objects interests of 

 itself and because of its beautiful structure. 



Moreover it often happens that an instrument which, when first 

 purchased, was of very fair quality, has, through ignorance and 

 carelessness, become so soiled and dimmed that it no longer serves 

 the purpose intended. On more than one occasion have we seen a 

 fine microscope leave the dealer's hands in excellent order, and re- 

 turn in a week entirely unfit for use. Microscopes in this condition, 

 instead of being a source of instruction and pleasure, are an eyesore 

 and an occasion of annoyance. They continually serve as reminders 

 of awkwardness and failure, of wasted time and ill-spent money. 

 And yet with proper instruction and a due amount of care all this 

 might have been avoided. 



It is also a fact to be regretted that heretofore the microscope has 

 not been extensively employed in the arts, and in everyday life, 

 simply because practical men have not been taught how to use it, 

 and consequently have been unable to avail themselves of the advan- 

 tages which it offers; but if carefully and judiciously selected, and 

 properly handled, it is capable of affording an amount and kind of 

 assistance which cannot be safely neglected. It may be made to aid 

 in the examination of raw materials, and of the finer kinds of work ; 

 it will enable us to measure spaces which would otherwise be inap- 

 preciable, and this, in an age when even in ordinary machine shops 

 the thousandth part of an inch is frequently an important quantity, 

 renders it indispensable to the careful and skillful mechanic; on the 



