In “Wenham’s Radial” Microscope the chief aim has been directed towards providing a very considerable range of effects, both in altitude and azimuth. The leading principle followed throughout in the construction of this form of stand is that of facilitating the work of the microscopist and of obtaining the maximum range of oblique illumination in all directions. This is fairly well attained by causing all the movements of inclination and rotation to radiate from the object as a common centre. Thus it has been found possible to combine seven radial motions, so that when the instrument is inclined backwards, as in Fig. 61, or placed in the horizontal, as in Fig. 62 or rotated from in the brass plate, a pencil of light from a fixed source shall always reach the object and pass to the objective. The stage is made to rotate completely, and its rectangular motions are effected by milled heads acting entirely within the circumference. The sub-stage is mounted on the Zentmayer system, with two centring screws, by means of which the optic axis is secured. It is also provided with rectangular and rotating motions. The coarse adjustment is that of the Ross-Jackson form--a spiral pinion and diagonal rackwork, while the fine is on an entirely new principle designed by Dr. H. Schrœder. [Illustration: Fig. 61.--Ross’s Wenham Radial Microscope.] The “Ross-Zentmayer Microscope” is a thoroughly substantial and practical instrument, combining elegance of appearance with strength and firmness. [Illustration: Fig. 62.--The Ross-Wenham Radial Microscope.]