REQUISITES FOR WORK. 



It is the intention to make such recommendations 

 in this chapter which, if not absolutely necessary, will 

 be found convenient and will aid in facilitating work. 



One of the first requisites for the proper use of the 

 microscope, is a thorough knowledge of its parts and 

 an acquaintance with the optical principles involved. 

 For this purpose the writer earnestly requests a 

 perusal of the preceding pages, and is convinced that 

 in cases where no previous knowledge of the instru- 

 ment has existed, work will be .done with far more 

 ease, in much less time, and with a greater degree of 

 satisfaction. Ignorance of the instrument's capacity 

 may lead to an idea that it is inferior and thus be the 

 means of its final abandonment ; and in place of the 

 anticipated pleasure there may arise a feeling of bit- 

 terness and disappointment for all future with every- 

 thing connected with it. There are innumerable cases 

 of this kind and they have induced a belief that it is 

 difficult to acquire a practical manipulation of the 

 microscope, whereas such is not the case when a lim- 

 ited time, properly applied, is devoted to it. 



Working" Table. A firm table should be used, 

 preferably one with three legs, as this will always be 

 firm no matter how uneven the floor is, and if it can 



