This simple monocular microscope by W. Johnson corresponds to the model awarded by the Society of the Arts in London.
The microscope is mounted on a wooden base which, in addition to making it more stable, makes it easier to insert into the wooden case. Its macro focus system is achieved by means of an endless screw, which ends in two side wheels and acts on the rear rack of a triangular axis. The micrometer screw acts on the lower part of the optical tube and is located at its rear. The W. Johnson optician at 188 Totenham Court Road was the supplier of London University Hospital at the time.
History. In 1855 the London Society of Arts with the intention of popularizing the use of the microscope, an apparatus that used to be of very exclusive use due to its cost, convened an award «for the best monocular microscope manufactured that had a price of less than 3 guineas» (one guinea equaled 2.5 pounds).
The apparatus should meet the following specifications: have two magnifying lenses and should be capable of being disassembled and stored in a compact box. Its manufacture had to be carried out at a small cost and the winner had to commit to putting it up for sale at that price.
Numerous manufacturers participated in this contest, which was won by Robert Field from Birmingham. The popularity of this microscope was such that many manufacturers designed and manufactured this same model with small variations from the original, becoming known as the «Society of Arts’type microscopes». It was a very frequent model until the beginning of the 20th century.
Within this collection you can find some copies that belong to that model, as well as the next one (number 13) that was made by J. T. Slugg and put it on sale for a price lower than two guineas.