The following was extracted from E. J. Spitta : Microscopy, The Construction, Theory, and Use of the Microscope, 1920
Swift & Son's
Portable Histological Microscope (Fig. 202) of
great excellence. Although primarily designed for
the stud of Histology, it is perfect as an
all-round instrument. It has the peculiar feature
first of having four legs, and secondly of being
collapsable, for it can be packed away in the
smallest mount of space imaginable, although a
little practice is necessary to do this, as a study
of Fig. 203 will lead the reader to understand. It
may therefore claim admission into the class of
Portable microscopes. Constructed for the short
tube, it can be extended for. an optical
tube-length of 10 in., which makes just a trifle
too short for the convenient and scientific use of
long-tube objectives, without an additional
draw-tube or the use of Zeiss "sliders" or a
revolving nosepiece, either of which increases the
length sufficiently.