64 



LABORATORY MICROSCOPES. 



\_CH. II. 



hive in it many other objects which are more easily seen, as the red blood corpus- 

 cles or particles of vegetation or dirt in the case of the blood preparation or of the 

 amoeba. 



61. 



Figs. 61-63. Sectional Views of the two Forms of the Marker. 



Fig. 61. The simplest form of marker. It consists of the part SS with the 

 milled edge (M). This part bears the Society or objective screw for attaching the 

 marker to the microscope. R. Rotating part of the marker. This bears the eccen- 

 tric brush (B) at its lower end. The brush is on a wire ( W). This wire is eccen- 

 tric, and may be made more or less so by bending the wire. The central dotted 

 line coincides with the axis of the microscope. The revolving part is connected 

 with the " Society Screw " by the small screw (S). 



Fig. 62. 55, R, and B. All parts same as with Fig. 61, except that the brush 

 is carried by a sliding cylinder the end view being indicated in Fig. 6$. 



64. 



65- 



Figs. 64, 65, 66. Specimens Showing the Use of the Marker. 



In Fig. 64 a section of a series is marked to indicate that this section shows some, 

 thing especially well. In Fig. 65 some blood corpuscles showing ingested carbon 

 very satisfactorily are surrounded by a minute ring, and in Fig. 66 the lines of a 

 micrometer are ringed to facilitate finding the lines. 



