The following was extracted from he Microscope and Its Revelations, W. B. Carpenter, sixth ed., Vol 1, 1883
Ross's
(Zentmayer) Student's
Microscope. Another instrument of superior
make (Fig. 43), has lately been introduced by
Messrs. Ross, with the view of affording to the
Student the advantage of the ' swinging tail-piece
for oblique illumination,' devised by Mr.
Zentmayer; of which a fuller description will be
given in its application to their First-class
Microscope. This tail-piece swings round a
pivot which serves for the attachment of the stage
to the limb; and at the back of the limb is a
milled-head working on the projecting end of this
pivot, by tightening which the stage may be firmly
fixed in its ordinary horizontal position, whilst
by loosening it the stage may be made to incline to
one side or the other. The ' tail-piece ' carries,
between the mirror and the stage, a ' sub- stage,'
fitting into which may be screwed an ordinary 1
inch, 1 1/2 inch, or 2 inch Objective, which
answers the purpose of an Achromatic condenser; and
when a pencil of light reflected from the mirror
has been made by it to focus in the object, the
swinging of the ' tail-piece ' to one side or the
other will give any degree of ofcliquity to the
illuminating pencil that may be desired, without
throwing its focus off the object, as this lies in
the plane of the centre round which it turns. The '
tail-piece' may even be carried round above the
stage, so that light of various degrees of
obliquity may be concentrated upon opaque objects.
The object-platform of the stage is of glass, and
rotates round the optic axis of the microscope; so
that the object may be illuminated by oblique rays
from any azimuth. A mechanical stage may be added,
if desired. The workmanship of this simple model
is of the highest class; and there is little real
work, of which, in the hands of an observer who
knows how to turn the instrument to the best
account, it may not be made capable, by the
addition of a Polariscope, Paraboloid, and other
accessories, which its Sub-stage adapts it to
receive.
The example shown on this page is a more advanced model than that describe above having a focusing and centerable sub-stage fitted with an achromatic condenser and Mayall's patented mechanical stage.
Exreacted from Hogg, The
Microscope, 14t Edition
Swinging Sub-stage, or Tailpiece.- The Swinging sub-stage,
although revival of an invention contrived by Mr.
T. Grubb some twenty years ago, has been very
generally adopted, since it is thought by
manufacturers to be an important and useful
addition to the more perfected forms of
instruments. This tailpiece, represented in
sectional elevation fig. 27, consists of
S, the limb carrying the body,
with coarse and fune adjustments;
A, the stem carrying the
sub-stage, B, and mirror.
A is attached to
S by the sleeve or socket
I,. clamped by the nut
J, and on I
A may be swung sideways in either
direction to the right or left, either below or
above the stage, the axis of revolution which is
the line X Y;
that is, a line in the plane of the object to be
viewed on the stage C, intersected
by the optical axis of the instrument; that is, the
line N O, passing
through the centre of the body and the objects
glass of the microscope The stage
C is also attached to
S by the pin C1,
terminated by the screen C2, which
pin passes through the contre of the socket
I, and moves therein so that the
stage C may readily turn in either
direction in conjunction with or independent of
A, the axis of its revolution
being also the line X
Y. By this kind of arrangement the
stage C and the stem
A can be set at any angle to the
axis of the microscope, either below or above
X Y, intersecting
the plane of the object to be viewed, and
relatively to each other, and when so set the stage
C can be clamped at the desired
angle by the nut D on the screw
C2 acting on S
and the collar K.
Microscopes
incorporating the Zentmayer swinging sub-stage were
first offered by the Ross firm in the 1880
catalog.