THE MICROSCOPE. 7 



Defining power, not the magnifying power, is the thing to 

 care for ; we want to see the real structure of an object, not 

 an exaggerated representation; and those are the best glasses 

 which transmit clear light, give a perfectly flat field, and 

 by which we see sharp distinct lines in the object we are 

 investigating. 



I will but add a few practical hints on the management 

 of the microscope : 



Do not imagine that an expensive apparatus is necessary. 

 The greatest discoveries have been made with the simplest 

 instruments. 



Have good object-glasses, and do not waste money on an 

 elaborate stage. 



Use low powers in preference to high ones, unless abso- 

 lutely necessary ; and, remember, we do not want objects 

 magnified so much as we want them defined. A clearly- 

 defining low power is the best working glass. 



A few simple tools will be sufficient for all purposes of 

 dissection and examination, viz. 



Slides of glass. 



Circles and squares of thin glass. 



A pair of forceps. 



A lancet. 



A few needles, fixed in handles. Split one end of a 

 match, and tie the needle in with some waxed silk. 



Two or three camel-hair pencils. 



Six watch glasses. 



These are all that are absolutely necessary for daily 

 study. 



FOR MOUNTING OBJECTS. 



This need not be a difficult or expensive process ; but to 

 succeed with insect preparations time and experience are 

 essential. The easiest beginning is with vegetable speci- 

 mens cuticles, pollen, &c., and with palates which are 

 mounted in fluid. 



You must have a turn-table, price 6s. to 8s., and make 

 a cell on each glass slide you mean to use, with gold size 



