166 



I have stated before that this movement is applicable to any con- 

 struction of stage-guides ; I will now say a few words respecting its 

 application to the stage with dove-tail slides having plates moving 

 vertically and horizontally. 



If applied to this kind of stage, it is as well to have the upper plate 

 move vertically, for in that case the longer arm of the lever and its 

 knob have to balance that plate only. But should the middle or se- 

 cond plate move vertically, then the lever must be sufficiently heavy 

 to support the two plates when the stage is in the position represent- 

 ed in fig. 1. 



Fig. 3 represents this mode of movement applied to a three-plate 

 stage. 



END OF VOL I. 



K. NEWMAN, PRINTER, 9, DEVONSHIRE STREET, BISHOI'SC. A 1 t. 



