336 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
attached to both movements. The object-carrier is so arranged that the 
slide rests upon the surface of the Microscope-stage, and may be used 
in immersion contact with the condenser if desired. The stop against 
which the slide rests is adjustable, permitting the use of slides of 
various sizes. The object-carrier has an extraordinary range, the move- 
ments being 35 and 60 mm. respectively. The stage is held in place 
on the Microscope by a solid metal clamp, open at one side, which slips 
upon the base washer of the arm of the Microscope, in such a manner 
that the simple tightening of the thumb-screw at the back locks it 
immovably. The clamping device may be left attached to the Micro- 
scope permanently, and the object-carrier removed by simply racking 
it out of the slide. This feature is of great value, as the mechanical 
stage is necessary for search work, counting, dc., while an unobstructed 
stage is required when examining bacterial cultures in culture dishes, 
using watch-glasses on the stage of the Microscope, &c. 
Powells Iron Microscope. — The President sends us the ^following 
addendum to the account of Powell’s Iron Microscope, which was exhi- 
bited at the February meeting * : — “ I have found the origin both of the 
See p. 209 and figs. 44 and 45 of the current volume of the Journal. 
