From what may be called a crude attainment of 

 these three purposes, the construction gradually became 

 more complex. Many additions have been made which 

 have proven useful and have remained, while others 

 have been discarded. As the first microscope was 

 constructed in 1590, it has required nearly three 

 centuries to bring the instrument up to its present 

 general form, and it is interesting to note that many 

 improvements which have been introduced within the 

 last forty or fifty years have been used and lost sight 

 of within this time. 



While certain parts are necessary to make up a 

 modern instrument, no one design of construction is 

 followed. The forms are innumerable, each maker 

 following his own inclination in variety, design, number 

 of parts, and material. For the latter, brass predomin- 

 ates, although bronze and iron are used to a consider- 

 able extent. The first two metals are usually highly 

 finished and, as they easily tarnish, are protected by 

 lacquer, which not only is serviceable in this direction 

 when of proper composition and rightly applied, but 

 offers a means of ornamentation. Iron is covered 

 with a heavy coating of japan and being dark is on 

 this account often recommended as being agreeable 

 for the eyes. 



The entire apparatus, including the optical parts, 

 is called a microscope, whereas, without them, it is 

 termed a stand. 



28 



