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The All-Brass Universal Microscopes of Benjamin Martin, 1756-1782

Benjamin Martin (1704 - 1782) was one of the most innovative instrument makers of the 18th century. In 1738, he produced a microscope while living in Sussex and was among the first to use the term 'Universal' to describe it. In 1742, he published his work, Micrographia Nova, which featured illustrations of his second version of the "Universal Microscope." The microscope was named so because the arm supporting its optical tube was mounted on a ball-and-socket joint, allowing for vertical or horizontal rotation. Martin also added a micrometer to his early microscopes, which became a signature feature. In 1756, Martin moved to London, where he faced fierce competition from his famous peers as a maker of instruments and lecturer and as an optician. His advertisements for spectacles appeared alongside Ayscough's scathing criticisms in contemporary newspapers.

Benjamin Martin, The First All-Brass Universal Microscope, ca. 1763 (Inv. YG-19-005)


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Martin Universal 3a.jpg

Martin developed different versions of the 'Universal Microscope' that could be used to observe transparent and opaque objects and motile organisms in ponds or seawater. He produced several iterations of this microscope, which eventually became known as simple, compound, or aquatic versions. Martin's earlier versions of the Universal Microscope were relatively basic compared to later models. He announced the third version of the Universal Microscope in 1752, but no illustrations were ever published, so its exact construction remains unknown. In 1759, Martin published an engraving of his all-brass "Universal Compound Microscope" in the Philosophia Britannica. This microscope featured an innovative planoconvex lens of long focal length that formed the objectives' rear element. This lens was placed at the top of the snout, known as 'Martin's Pipe,' in many of his microscopes. The microscope also featured a Hevelius-screw type of fine focus and a winged stage that could swivel in an arc, preserving the function found in his second universal microscope.

This microscope was produced sometime between 1759 and 1768 and has been subject to minor modifications. It set the foundation for models that followed. The instrument is identical to the one sold to Joseph Priestly, a famous scientist, in 1767, which has been well-documented and signed. The compound tube can be moved forward, backwards, or even removed entirely to allow for compact packing in its sharkskin-covered case. Additionally, it can be tilted to aim horizontally. The instrument is estimated to have been produced between 1760-67 or around 1763. This can be deduced based on the fact that Martin started producing instruments with the between-lens after 1759, but before 1768 when he began regularly using rack and pinion focusing.

This microscope is unique because of its baluster-turned pillar, round base and the fact that the knob which holds the stage is identical to the ones that clamp the coarse focus and hold the tube assembly on the arm. Some examples of the instrument have conical snouts, while others have cylindrical ones that accept a Lieberkühn. These features may relate to Martin's development of a Lieberkühn holder that would attach to the front of the stage, a feature frequently found in his successive 'Universal' instruments and later on the Jones 'Most Improved' model. 
The microscope shown was often supplied with Martin's most significant and expensive 'optical cabinet,' which he called 'a portable optical apparatus.' It contained a solar microscope, the best compound microscope, and a single (screw-barrel) microscope, all set in a large fish skin case. 

The microscope is supported by a folding tripod base and a pillar. The double concave mirror is mounted on one of the legs of the tripod. The body arm is attached to the top of the pillar and can move in an arc, making the microscope "semi-aquatic". A hinge allows the body tube to be used horizontally and the compound body can be replaced with a simple lens. The stage can be moved using a rack and pinion. The rack is located on the inner face of a slot cut into the vertical pillar, and the block carrying the pinion and stage slide into this slot. Fine focusing is achieved by clamping a bracket attached to the stage to a thin vertical rod, which can be moved by turning a milled-head screw. 

The microscope has an interesting optical design that includes an extra lens situated at the top of a narrow tube, between the objective lens and the two-lens eyepiece. The tube is referred to as 'Martin's pipe' and can be unscrewed to create a two-lens objective. The screw thread that fixes it to the instrument's body became the Royal Microscopical Society's Standard Objective Screw Thread. Martin's tap and die were passed on from James Smith to the firm of Smith and Beck, who cut the first standard thread in 1858 for the Microscopical Society of London (later the Royal Microscopical Society). This information is based on the E.M. Nelson Collection.

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Gilbert & Co, Universal Microscope most likely by Benjamin Martin, ca. 1780 (Inv. YG-22-004)


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This microscope presents the latest form of Benjamin Martin's Universal Microscope. It depicts Martin’s last improvements, later to be taken by the Adams' Improved and the Most Improved microscopes (to be adopted by W&S Jones). It is featured with a compass joint uniting the pillar nearly at the lowest end of the limb. This Universal Microscope of the 1770s and on featured the Bonanni spring-loaded removable stage, which can be seen in the Whipple compendium. However, the example seen here is signed on the foot Gilbert & Co. London. This may be explained in different ways.

The auction sale catalogue of Martin's stock after his bankruptcy and death, which was held from March 8th, 1782, is available in the MHS copy (Millburn, 1986b, pp. 73-88; Herring, 1782). The catalogue lists the instruments that were sold during the five-day event, however, it does not mention the names of the buyers. The stock included around 40 types of microscopes, seven of which were compound or double microscopes of different kinds, along with several unfinished instruments. A few other microscopes were also included in the optical cabinets. It is safe to assume that many of the major retailers of that time, such as George Adams Jr., Peter Dollond, John, William, and Samuel Jones, etc., purchased a significant portion of the stock. It is also likely that these makers signed their names on the unsigned instruments they bought and sold to materialize their investment. John Jones & Son (later W. & S. Jones of Holborn) acquired several items from the auction and advertised at least a dozen Martin's book titles in their catalogues (Millburn, 1986b, p. 75). According to Millburn (ibid), many entries in their general sales catalogues of instruments between 1787 and 1795 were copied directly from Martin's. This indicates that John Jones and his son William Jones were among the major buyers at the Martin sales. However, it is possible that other significant instrument makers of the time, such as Dollond, Adams, Nairne & Blunt, etc., also attended the auction and acquired unknown numbers of Martin's instruments, including his microscopes. 

The Gilbert family had an outstanding reputation during the 18th and early 19th centuries for their exceptional skill in creating scientific instruments. John Gilbert the Elder was the first family member who gained prominence as a scientific instrument maker. He began trading in 1716 after serving an apprenticeship under John Johnson in 1709. He had several apprentices, including his son John Gilbert the Younger, who was enrolled in 1736. After becoming a freeman in the early 1740s, the family business started trading as Gilbert & Son. Unfortunately, there is no record of the elder Gilbert's date of death. 

It is highly likely that the younger Gilbert was already trading under his own name during the mid-1750s. He had several apprentices under his wing, including his sons John (III) in 1764 and William in 1769. William eventually succeeded to his Father’s business around 1776 after receiving his freedom and continued to trade solely under the Gilbert name until his Father’s death in 1791, after which he departed on a number of complicated partnerships for the next ten years. His first venture was the partnership of Gilbert & Wright. Gabriel Wright (1740-1803) was a former employee of Benjamin Martin. Given that Benjamin Martin had employed Wright for many years, it is likely that he felt the time was ripe for new horizons. Wright's first venture was in partnership with Gilbert & Wright. His dvertising in 1782 continued the patronage of Martin’s old customer base.

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Rochette Père, Paris, Rococo-styled Ormolu microscope employing Martin's optics, ca. 1795
(Inv. YG-22-023)

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This particular microscope, which seems to be the only one of its kind, was purchased in Paris. It utilizes the optical system of a Universal microscope made by Benjamin Martin, but the body has been replaced by an elaborate stand specially adapted for it. The stand features ornate Ormolu decorations made of gilded brass combined with lacquered wood, and even a crown-like ring was worn on the optical tube. Ironically, Martin's highly functional microscope became a showy luxury item designed for display in a parlor. It's a curious twist of history that an instrument from an English manufacturer who tried to make science accessible to all by creating affordable instruments ended up being transformed into a flashy item meant to showcase status and prestige.

There is a blurry signature on the brass plate attached to the wooden baseplate:
Rochette Quai de l'Horloge Paris
At this address, two manufacturers, a father and son, operated with the names Rochette Père and Rochette Jeune. Gaspard Rochette (1754–1822) is Rochette Père, while Rochette Jeune refers to Jean Rochette (fl. 1817-1860) who worked in the first half of the 19th century. Although Jean Rochette signed several microscopes, Gaspard Rochette is not known for making optical instruments. The rococo style and use of Martin's microscope in this case are more suitable for the late 18th century, hence to the father. It is likely that the optical part of the microscope was specially adapted to the stylish body and base based on a special order from a wealthy customer who wanted to turn his practical instrument into a display accessory.

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