During an exhibition in Nov 2000, Bill Davies showed his most elegant
version of a nineteenth century 'Library' or 'Museum' microscope which he had recently designed and expertly constructed. The
beauty and precision of its all-brass construction revealed Bill's
multi-faceted talents in the mechanical and microscopical arts as well as
his imaginative and original design approach. In addition, Bill had made a
bound, beautifully printed, 'old style' instruction manual and menu of the
many microscopic specimens contained in the Hertel disks.
These instruments were originally designed to simplify the observation of
prepared microscopic samples by groups of students, or visitors to museums.
Bill's instrument consists of a single microscope tube mounted vertically
above a horizontal brass turntable type stage, or "cassette", which holds
nine prepared slides in glazed circular apertures near its perimeter. When
using lower power objectives, the images remain in focus at each
successive, selected specimen position, so the microscope is easy to
operate by the lay observer. The brass cassettes, or "Hertel disks" may
quickly be changed to provide a range of specimens relating to specific
applications or fields of interest. The microscope shown, has a built-in
oil or candle-wax illuminator of surprising brilliance.
Different versions of these "Library " microscopes appeared during the
1800 s. One of the best known, now residing in the British Science
Museum, was designed and made by Thomas Winter of London, around 1835.
Winter's version uses a horizontal rotating drum which carries 40 prepared
slides.
