366 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



the ground. It is specially massive. A solid stage is made to swing 

 round, so that the object-glasses can be brought into focus on the 

 forging or casting upon which the foot or fork rests. To effect this, 

 an inside tube carrying the object-glasses slides within the outer barrel 

 and can be lowered to a sufficient distance. By means of a simple wire 

 rope strap the stand is rigidly held in any required position on the piece 

 of metal under examination. "When in focus the position of the barrel 

 is fixed by a screw at one side of the rack and pinion. When so fixed a 

 \ plate conical camera may be placed on the top of the barrel and photo- 

 graphs taken. 



Swift's New Compound Metallurgical Microscope.* — In this in- 

 strument (fig. 58), specially designed for the Royal Arsenal, Woolwich, 

 the optical tube is 2\ in. in diameter, and is divided to show the posi- 

 tion at which any objective will allow of an object being tilted without 

 going out of focus. The stage is so designed that after focussing the 

 object in the horizontal position it may be tilted or turned in any 

 direction without affecting the focussing. The ordinary slide is held 

 on the top of the stage by means of steel springs, while pieces of metal 

 are held in position by four clamping dogs sliding in dovetails and fixed 

 by small clamping screws. 



Fig. 59. 



Reichert's Medium Dissecting Microscope.! — This instrument 

 (fig. 59) has a rack and pinion adjustment, large stage, and a couple 

 of leather-covered hand-rests. The doublet has a magnification of 

 10 times. 



* J. Swift and Son's Catalogue, 1904, pp. 36-7. 



t C. Reichert's Special Catalogue, No. 25 (1904) fig. 19. 



