Jacob Huysen Cuff-type microscope, end 18th century

A Cuff-Type compound microscope attributed to Jacob Huysen, Dutch, third quarter 18th Century. This is a brass compound microscope with a rectangular pillar (19x9mm), mounted on a purple velvet-lined wooden box. The inside drawer is oak, the box itself is mahogany, and comes with original key. Optics consist of three lens systems: The objective lens, field lens, and eyepiece (consisting of two lenses). The instrument comes with 10 objectives, which are distinguished in two groups and marked in various ways through 5 in numbers and dots. One set can be screwed directly to the stage the other ones are screwed to an attachment to the stage. In a small ivory box glass plates are included. The stage can be adjusted with three different options. First is the movable arm, which can be adjusted by a screw with a magnifying glass. Second a spring plate, which can be clipped by two pins. Third a long table plate, also adjustable by two plates, for the four bone slides. At the bottom the mirror is attached to the stage and the box, it is elaborately decorated as a dragonesque figure. Focusing is accomplished by the rack and pinion which is part of the pillar supporting both the stage and the body tube. There is a window machined into the bottom support shaft through which you can view the moveable shaft (arrow). A friction spring presses on the movable microscope support arm. The body tube and stage of this instrument are styled after that of John Cuff, the well-known magnifying glass) English maker of optical instruments in the 18th century. This microscope would be considered large for a pocket microscope, but is certainly small enough to be called a portable instrument. It can be disassembled to fit into its rectangular box.This microscope is almost certainly an instrument of Jacob Huisen of Utrecht Holland (1739–1792). It is nearly identical to microscopes 144–146 described in Fourner, M. 2003. Early Microscopes, A Descriptive Catalog. Turner in Collecting Microscopes (1981, p56) describes an authentic Huysen instrument similar to this instrument (search for ‘Huisen’. First a Huysen microscope is part of the History of Science Museum, University of Oxford, inv.38583. One is possessed by the Boerhaave Museum, Leiden, inv. V07298.  Another one is possessed by the Golub collection.  Lastly, one is described in the Björn Uwe Kambeck collection.Measurements 28,4 x 15,4 x 25 cm.