62 



THE MICROSCOPE AND ITS ACCESSORIES. 



Ross AND Co.— The excellence of Messrs. Ross's instruments, 



considering the reputation of the makers, 

 need not be enlarged on. 



Fig. 12 illustrates their No. 4 stand. A 

 general idea of the arrangement can be 

 seen by glancing at the figure. This 

 instrument is made on the lines of what is 

 known as the Ross-Jackson model. The 

 body of the stand is supported between 

 two pillars arising from a " bent claw " 

 foot. It has a rack and pinion coarse 

 adjustment, a screw fine adjustment, a 

 draw-tube, and a concentric revolving 

 stage. The sub-stage apparatus is attached 

 to a swinging tail-piece, thus being rapidly 

 removable if direct illumination from the 

 mirror is required. 



Fig. 13 is a somewhat similar stand, but 

 supported on a tripod foot. This form of 

 foot is greatly to be preferred, being far 

 steadier than any other. The coarse and 

 fine adjustments and the stage are the 

 same as in Fig. 7 ; but there is no tail- 

 piece for sub-stage apparatus. It has, 

 instead, a brass collar affixed to the under- 

 part of the stage, into which a revolving 

 plate of diaphragms is inserted. 



J. Swift and Son. — Fig. 14 illustrates Messrs. Swift's Advanced 

 Students' Microscope. The stand is supported between two 

 pillars. The coarse adjustment is by rack and pinion, the fine 

 adjustment being by differential screw. The body-tube is short 

 enough to allow of Continental objectives being used, while the 

 draw-tube will bring it up to the full English standard. It has a 

 Nelson's horse-shoe stage, carrying a sliding-frame with spring clips. 

 The tail-piece is grooved to receive a sliding bar, bearing a sub- 

 stage fitted with centring screws (a rack and pinion adjustment 

 can be had in place of the sliding movement). The sub-stage as 



