ARRANGEMENT OF APPARATUS. 105 



We shall now point out a few of the advantages 

 of our own method. 



Any microscope can be fitted with the necessary 

 additions at a trifling cost, the amount depending 

 on what can be done by the possessor himself; in 

 fact, the majority of first-class instruments, already 

 possess these additions. 



The same apparatus answers with every method of 

 illumination, it can be made to assume any position, 

 the use of oblique light is facilitated, and the em- 

 ployment of photography with objects in fluid be- 

 comes possible. 



On account of its portability the several changes 

 are easily made, while the simplicity of its construction 

 prevents the possibility of its getting out of order. 



In the following pages we have adopted the plan 

 of describing a different method of illumination, and 

 arrangement of apparatus with each objective, in 

 order to illustrate the employment of different 

 sources of light; not on account of any advantage 

 gained by using the illumination and arrangement 

 described with that particular objective. For in- 

 stance, sun-light, lamp-light, and electricity, give 

 equally good results with the eighth immersion if 

 the adjustments of the microscope are suitable for 

 this objective, and the conditions of their employment 

 identical. 



With regard to illumination, we most decidedly 

 recommend the use of an ordinary parafin lamp, 

 with one broad single wick, one and a quarter inch 



