ON SMITH AND B E C K ' S ACHROMATIC MICROSCOPES.
273
period their artificial generation is very uncertain. This little experiment is a very simple and instructive one, and may be performed by any one who will take the trouble to follow out these
instructions."
But the most useful part of this volume to the advanced
student is an appendix, in which the author gives a classification and scientific description of the fungi which have been
move generally alluded to in the previous pages of the work.
For those who have not their hands already full of work, and
prepared to strike into a new field, we promise them a mine
of interest in Mr. Cooke's pages, and a world of undiscovered
beauties to work in.
A Treatise on the Construction, Proper Use, and Capabilities
of Smith, Beck, and Beck's Achromatic Microscope. By
RICHARD BECK.
London : Van Voorst.
IT is not often that the makers of scientific instruments
are the most skilful exponents of the principles of their
structure or the authors of discoveries made by their use.
Nevertheless, many departments of practical science afford
exceptions to the rule—none more so than the inventors and
makers of improvements in the microscope, and every microscopist will recollect that Joseph Jackson Lister, after he
had overcome the difficulties of making a compound achromatic microscope, set to work to make observations therewith, and produced a series of highly interesting observations,
which were published in the ' Philosophical Transactions/ on
some of the lower forms of Tunicated Mollusca. It may not
be generally known that, so little was the microscope appreciated as an instrument of research by those who conducted
the business of the Royal Society in 1838, that when Joseph
Jackson Lister sent his first great paper to that society, on
the construction of achromatic glasses, and accompanied
it with various observations on the mechanical parts of
the instrument, the paper was sent back to him on this
account, with a request that, as the microscope was, after all, a
mere toy, he would omit any reference to what he considered
mechanical improvements. In this fact we see how dangerous it might be to commit the interests of science to any
select body of men, and that it is only in the perfect freedom
of voluntary association that science can progress. The
Microscopical Society was shortly after founded, one of the
274
ON SMITH AND BECK.'s ACHROMATIC MICROSCOPES.
great objects of which was to cultivate those scientific researches by which this " mere toy" of the Royal Society
might be made available for the profound scientific researches
for which it was adapted. One of the indirect results of the
rejection of the Royal Society of Mr. Lister's practical suggestions was his connection as friend and adviser of certain
microscope-makers in London. Prom these houses have
issued the most perfect microscopes that have been constructed
in accordance with Mr. Lister's principles. No one of these
houses has been more distinguished than that of Smith,
Beck, and Beck, and in Mr. Richard Beck, the author of the
present volume, we have a remarkable instance of the combination of the finished mechanician and accomplished observer.
Previous, however, to Mr. Beck entering the field as an
author, the late Mr. Andrew Ross, the founder of one of our
great microscope-making houses, had written a valuable work
on the physical principles involved in the manufacture and
in the structure of the microscope. This work originally
appeared as an article in the f Penny Cyclopaedia/ and may
claim priority over all the works that have been devoted to
the history and structure of the microscope during the last
quarter of a century.
The present work is not intended to serve as a history of
the manufacture of microscopes or of microscopic observations of optical principles. But it gives an accurate account of
the structure and capabilities of Smith and Beck's instruments.
It is hardly necessary that we should say that whatever the
microscope demands for its intelligent and successful application is provided by this establishment, hence this work
becomes a most useful text-hook to all who are seeking for
the best means of conducting microscopic researches. The
work consists of a detailed account of the various parts of
which a microscope is composed, and commences with a
description of first- and second-class achromatic microscopes.
All the apparatus for the working of such microscopes is
described, and is followed by plain directions for the use of the
microscope. These directions include remarks on the various
kinds of illumination, and the apparatus which have been
invented for assisting illumination. In the remarks made by
Mr. Beck on illumination reference is made to the use of testobjects for measuring both the defining power of the objectglasses and the means of illumination employed. Whatever
instruments are employed, these remarks will be found useful. A considerable space is devoted to the consideration of
the subject of polarized light to the microscope, and all the
apparatus required is described. Mr. Wenham's binocular
ON SMITH AND BECKYS ACHROMATIC MICROSCOPES.
275
microscope is then described, and the principle of its construction defended against the attacks of those who are in
favour of the old monocular form of instrument. The increased demand for binocular instruments seems to indicate
that the old arrangement is doomed. Men of fifty, who have
for thirty years used the monocular instrument, may repudiate
the more recent instrument, but as long as the fact remains
than men see better with two eyes than one so long will it
happen that those who have once appreciated the advantages
of a binocular microscope will not think of going back to the
instrument which only allows the use of one eye.
After describing first-class instruments, Mr. Beck then
gives an account of the third- and fourth-class instruments.
Most persons are aware of the nature of the instruments
which, under the name of the Popular, Universal, and Educational Microscopes, have been manufactured by Messrs.
Smith and Beck. The work finishes by a chapter on the
instruments and materials used in mounting objects.
To those who are the fortunate possessors of one of Smith
and Beck's first-class compound achromatic instruments this
volume will be found exceedingly useful in enabling them to
understand the applications and capabilities of their instrument. To all interested in the structure of the microscope
this volume, giving an account of the actual work of one of
those great houses to which Mr. Lister has succeeded in
giving something of the reputation of his own great name,
will be found to contain a vast amount of useful and interesting matter.
The work is published in large octavo, and is illustrated
with twenty-eight most beautifully executed plates. Most of
these are devoted to the illustration of the apparatus described,
but some of the plates are devoted to the illustration of testobjects. Some of these are remarkable for the faithful
manner in which microscopic structure is depicted. We
would especially refer to the beautiful drawing of the tarsus
of the Tegenaria atrica, a very common form of spider, in
which the various minute hairs covering this organ are given
in the most complete and accurate manner. The figure, again,
of Arachnoidiscus Japonica, a beautiful diatom first found in
sea-weed from Japan, is quite an achievement in illustration,
and seems to indicate the importance of giving different
aspects of even minute objects like diatoms. There is also a
beautiful plate of Polycistina on a dark ground, and another
of polarized objects, all instructive in relation to the use of
the microscope, and suggestive of the way in which microscopic objects may be represented.
VOL. V.—NEW SEE.
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