THE NEW ACME STAND. 89 



The main stage has also conveniences for centering. 

 Furthermore, a solid plug is furnished which screws 

 into the well-hole, and forming when desired, a solid 

 stage. This plug has an "X" engraved thereon for 

 centering purposes. 



The sub-stage proper, as well as the concave mirror, 

 are attached to a swinging bar by dove-tailed blocks, 

 The slides having compensation for wear, the sub-stage 

 can be centered. It is one and one-half inches in diam- 

 eter and is fitted to carry any of the accessory pieces 

 usually accompanying a first-class outfit. The sub- 

 stage and the mirror both slide with easy friction on 

 the swinging bar. 



The swing-bar traverses the face of a circle of brass 

 placed at the rear of the stage, the centre of this circle 

 being in the plane of an object placed on the stage; 

 the centre of this circular plate is solid, that is to say, 

 it presents a solid core of about one inch diameter; 

 outside of this an angular groove is cut therein, in which 

 .swings the heel of the swing bar, the method of at- 

 tachment of the swing bar to the circular plate giving 

 great solidity as well as firmness in motion. Thus it 

 will be seen that the " swinger" swings not on a centre 

 but around a centre. This part of the mechanism needs 

 only to be seen to be appreciated. 



The mirror is of course removable, and a toy candle- 

 holder is provided to take its place for the measure- 

 ment of apertures. 



A supplemental circular and revolving stage plate is 

 .also furnished, which "slips" on and off instantly as 



