The Watson firm
first manufactured this type of microscope in
1891 at the suggestion of the renowned Belgian
microscopist Henri van Heurck (1838-1909).
When first introduced, the microscope
incorporated a continental (horseshoe) style
base, but, as with the present example, stands
with an English tripod base were also produced
and became the standard form.The microscope is
constructed in brass with bright lacquered and
oxidized surface finishes and is about 16 inches
tall when set up for use with the draw tubes
partially extended as shown in some of the
photos. The main focus is by rack and pinion and
the fine focus is by calibrated micrometer screw
(1 rev, 1/13 mm). There are two drawtubes with
the main drawtube calibrated and having movement
by rack and pinion. The substage is focused by
rack and pinion, has a fine focus by micrometer
screw located at the side of the stage, and has
The following was taken from the 1923 Watson & Sons catalog:
The Van Heurck is the most completely-fitted model which we make, and represents all that is most modern in microscope design and manufacture.
The aim in its construction has been to present, in the most efficient form possible, mechanical movements of complete and comprehensive description, in a design of maximum rigidity, and to maintain every feature in the most up-to-date manner, and we can assert unhesitatingly that the complete control which is afforded in working enables the finest results to be secured with a rapidity and comfort which is unique. It lias brought the most gratifying testimony from many of the leading microscopists of the day, and this, coupled with the fact that the Van Heurck is now used by many of the foremost workers in every branch of research, is a sufficient guarantee of the perfection attained.
This Microscope was first made by us to tho specification and order of the late Dr. Henri Van Heurck, the celebrated Microscopist, of the Botanical Gardens» Antwerp, for conducting the researches for which he gained such distinction, an for his high-power Photographic work.
Photo-Micrography, especially with high powers of large aperture, demands a working excellence and accuracy of the highest grade in every part—it is, in fact, the severest test to which a microscope can be put. In the construction of this Instrument the usual causes of failure have been eliminated. It will at once be recognised that the precision which is requisite for high-power photography and which is provided in this Instrument, is of immense value to the ordinary visual worker, for it enables him to secure the fullest and most effective means of conducting his researches. Especially does this apply to Laboratory work, in which reliance has to be placed on the results obtained ; and to those who are doing original and accurate work, this microscope will be found to embody every convenience for rendering such work more easy and exact.
Elsewhere on this
website is another example of the
Watson Van Heurck No.1 with a less elaborate
arrangement of the stage.
This microscope originally resided at The National Physical
Laboratory (NPL) in Middlesex, UK.
The NPL was founded in 1900. One of the mandates
of the Laboratory from its beginning was to
evaluate the leading optical instruments of the
time. It is possible, given that this instrument
has seen little if any use, that this Watson Van
Heurck No.1 was among those instruments.
Alternatively, it could have been one of the
Laboratory's working instruments used for taking
physical measurements. The instrument is equipped
with an advanced centering stage where the
movements are fully calibrated reading by
verniers to 1/10th of a mm. The divisions of the
circumference of the stage in degrees can be read
to by a vernier to 5 minutes.The stage rotation
is by pinion working on a circular rack.