Compound achromatic microscope, No. 1 ‘Van Heurck’

Description

In mahogany box with its lock and key.
The Antwerp microscopist Henri van Heurck (1838-1909) needed a microscope that was optimised for observation and photography of diatoms, unicellular algae with a skeleton of silica. The English instrument maker Watson started making this type of stand after the directions of Van Heurck around 1890.
The instrument is very solidly and well built because of the desired mechanical stability. In order to be able to discern very small structures in diatoms the condensor can be positioned out of the optical axis, there is a rotating and adjustable mechanical stage with fine movements in both the X and Y axis. The tube length is adjustable with rack and pinion to compensate for the spherical aberration of objectives. Coarse adjustment acts by rack and pinion in the usual way. Fine adjustment is by means of a micrometer screw acting on a lever which moves the block carrying the coarse adjustment and the body tube. There is a triple objective changer.