82 



PRACTICAL MICROSCOPY. 



all sides. In order that this may be done easily, Messrs. 

 Beck make what is called a stage mineral-holder (Fig. 67), 

 one of the jaws being movable in a right line, so that it 

 may clamp any sized specimen, and by turning the milled 



FIG. 67. 



head of the jaw the mineral is made to revolve. Fig. 67 

 will perhaps show more clearly the action of this holder 

 than any description can do. 



FIG. 68. 



Morris's rotating stage (Fig. 68) often serves the purpose 

 of stage forceps. In its improved form it can be used for 

 both opaque and transparent objects. Small flies, larvae, 

 beetles, &c., can be affixed to the cork by means of a 

 small pin, or with gum, and as the stage moves upon a 

 secondary plate by means of a ball-and-socket joint, the 

 object can be placed in a variety of positions hardly 

 possible by any other means except the disc-holder of 

 Messrs. Beck. 



Beck's disc-holder, shown at Fig. 69, is for the purpose of 

 holding for examination under the microscope the small 

 discs upon which objects have been temporarily or per- 



