A cylinder iris diaphragm can be furnished in place of the ordinary cylinder diaphragm of Stand II, IIa and IIb at an additional cost of =$6.--= [Illustration: Iris diaphragm fitted to stage of stand III.] Stand III can be had with iris diaphragm fitted in stage, in place of the wheel diaphragm (see page 43) Additional price =$6.--= =_Complete Microscope Outfits._= The outfits comprised in the following pages are made up with achromatic objectives, which suffice for all ordinary needs. We are glad to supply any other combination of eye-pieces and objectives which may be preferred. The price of each outfit may be readily computed by adding together the cost of its various items. Microscope =stands=, without objectives, will not be sold separately. [Illustration: Stand A.--Universal Microscope.] =Stand "A".= Universal Microscope. In the construction of our new stand "A" we have taken special care to enlarge all the parts proportionately in order to secure strength and stability, at the same time adding to the beauty of the instrument. The upper pillar of the microscope is shaped in such a way as to form a convenient handle; and to increase the free working space over the stage, thereby allowing the examination of very large specimen and culture plates. A specially constructed mechanical stage larger than No. 98 may be attached, which is adapted for slides up to 2×4 inches (50×100 mm). The extra large dimensions of all the main parts of this microscope such as the base and stage etc., allow that freedom of movement so desired in a stand for photo-micrography. Both the body tube and graduated draw tube are very wide and permit the use of low power objectives to cover specimen of large extent; for the same reason the opening in the stage is very wide but can be narrowed down by a stop. The most important innovation on the microscope is the new fine adjustment device, which is unexcelled both in solidity of construction and accuracy of movement, representing the highest attainment of the designers and mechanics skill. Sectional cuts of this unique arrangement are shown in illustration (p. 26-27). All that can be seen on the exterior are two small milled heads mounted below and somewhat back of the two larger knobs controlling the rack and pinion (coarse) adjustment of the microscope. The knob on the right side is provided with a graduated drum _r_, indicating the movement of the fine adjustment.