Messrs. Ross have lately manufactured other forms of microscopes; one especially designed for those commencing the study of bacteriology (Fig. 59). This instrument is one of the steadiest among those lately constructed for high-class work. The circular foot and short stout pillar support the whole instrument, and a substantial knee-joint sustains the full weight in the upright or inclined positions, while the centre of gravity is by no means disturbed, and absolute steadiness secured. The stage is of the horse-shoe form, which affords convenient space for the fingers to lift the slide up while the oil is placed in contact with the objective. The fine adjustment is extremely sensitive, working smoothly and direct; this is entirely covered, to prevent injury by dust. The micrometer screw works directly in the centre of its fittings, the milled head being divided to read to 1/500 of an inch. The sub-stage is fitted with a new centring coarse and fine adjustment, so that when using high powers with the Abbe condenser accurate focus can be secured with the least amount of trouble. [Illustration: Fig. 59.--Ross’s “Bacteriological and Histological” Microscope.] The amount of activity shown during the last few years by opticians in the manufacture of new forms of microscopes renders it somewhat difficult to keep pace with improvements, some of which are novel. A further source of congratulation is that economy has all along been studied; so much so, that the instruments in question are within the reach of persons of moderate means. Messrs. Ross and Co. have taken a new departure in this respect, and their _“Eclipse” Microscope_ is an entirely new form of stand with a ring foot. This microscope has been produced for the especial use of students, and can be purchased for a moderate sum. It will be seen at a glance (Fig. 60) how steady this form of stand must necessarily be, since the centre of gravity is secured in every direction and inclination. The body-tube carries eye-pieces, numbered, of the Continental size and optical tube-length (160 mm.), for which the object glasses are adjusted, and a draw-tube extending to eight inches. [Illustration: Fig. 60.--Ross’s Rigid Pattern “Eclipse” Microscope.] The fine adjustment is independent of set screws, and not subject to derangement. It is extremely sensitive and direct in action, and from its construction is equal in perfection of working to the best that can be made. Its fitting, by a new contrivance, is completely covered at all points, being thus preserved from disturbance or injury by dust. The Eclipse is furnished with two eye-pieces, 1′′ and 1/4′′ object glasses of highest excellence and large angular aperture, both adjusted to a double nose-piece, so that they focus in the same plane; and a swinging mirror and stage iris diaphragm.