592 



Notes. 



Fig. 150 (scale ^) shows the horseshoe stage with the brass 

 plate in situ, and fig. 151 shows the brass plate when withdrawn. 

 In fig. 150 the X shows the optic axis, and it will be noticed that 

 from the X to the top of the sliding bar is 1^ in. (38 mm.), which 

 is equal to the distance from the X to the top of the stage ;. 

 therefore a slide 1^ in. (38 mm.) wide can be examined from it& 



Fig. 150. 



Fig. 151. 



top to its bottom edge; also f of an inch (19 mm.) of sideway 

 movement can be given to a slip 3 in. (76 mm.) long, on each 

 side, without causing the end to project beyond the stage. This 

 means that a 1^ in. (38 mm.) square on a slide measuring 3 by 1^ 

 (76 by 38 mm.) can be searched over without any portion of the 

 slip projecting beyond the edge of the stage. The two lines at 

 the bottom of fig. 150 indicate the sliding bar, but the lugs are not 

 shown. 



