108 THE NORTHERN MICROSCOPIST. 

A NEW MICROSCOPE. 
HE latest effort of Mr. Wenham, as an inventor, is an ingenious 
Microscope stand, lately made by Messrs. Ross & Co., and 
exhibited at the March meeting of the Royal Microscopical Society. 
It is called Wenham’s universal inclining and rotating Microscope, 
and its special intention is to obtain a greater variety of effects of 
oblique light than has hitherto been obtainable without losing sight 
of the object under examination. The base consists of a circular 
plate, a ring of which rotates within a graduated arc, and carries a 
vertical bearer with it. Within the jaws of this bearer slides a 
sector, from near the centre of which rises radially an axis, which 
carries the main limb of the Jackson pattern, holding the optical 
body, stage, swinging sub-stage, and mirror bar. By means of the 
sliding sector the optical body can be placed in any inclination 
from the vertical to the horizontal position, and, in combination 
with the axial motion at right angles to the former, it can be placed 
in any conceivable position within a quarter of a sphere, the centre 
of which is the focal point of the objective. The limits of this 
motion can be extended by rotating the instrument on its base. 
The centre of all these motions, both circular and axial, is also 
the centre of the stage, at about the thickness of any ordinary 
object slide above it ; so that in whatever position the optical body 
be placed, the object under examination will always remain in the 
same place, whilst the object plane may be tilted about in every 
direction within certain limits. The advantage of this arrangement 
will be evident when finely striated objects like diatoms are examined 
by direct light from a fixed source transmitted through the object ; 
because in that case, by merely altering the position of the optical 
body, every variety of light as to obliquity and direction can be 
obtained on one side of the object, and, by a rotation of the stage 
through 180°, on the other side also. If the mirror and sub-stage 
condenser be interposed in the ordinary way, the inclination of 
the mirror will, of course, require altering with every alteration of 
position of the optical body; but this can be done gradually 
without losing sight of the object. The mirror bar can, however, 
be clamped to the sector, when the fixed mirror will still transmit 
its light to the object, whilst the optical tube is moved laterally 
upon the axis passing through the object. The instrument: is — 
furnished with Ross’ diatom stage, which allows extremely oblique — 
light to be transmitted to the object from beneath. The coincidence 
of the optic axis with the centre of the rotating plate is secured 
by adjusting screws; and the mechanical motion of the object 
carrier, which is very thin, is effected in rectangular directions by 
screws placed within the circumference of the stage, so as not to 

