Withering-type botanical microscope, 1780
The “Withering-type Microscope” is named for its inventor, Dr. William Withering (1741-1799), an English physician and botanist who graduated with a degree in medicine 1766 in Edinburgh. Inspired by the taxonomical work and systematic classification of Carl Linnæus (1707-1778), Withering (1776) applied the Linnaean taxonomical system of classification to British plants in a seminal, two volume work, A Botanical arrangement of all the vegetables naturally growing in the British Isles. The earliest reference to a small botanical microscope of Withering’s design appeared in the first edition of this book. There, Withering indicated this microscope was developed for field dissections of flowers and other plant parts. While there is no surviving example of this exact design, close relatives of this type do exist, made either completely of brass or of ivory with brass pillars. Ivory models can be tentatively dated to 1776-1785, as by 1787 a newer model with a hollowed stage in an all-brass configuration already predominated. In turn, it was preceded by the brief appearance of a transitional brass model but with solid stage of ivory or horn (seen here). This version is extremely rare and must have been produced in very small numbers. By 1787 all these varieties were not recorded anymore in the literature.
Withering-type botanical microscope, 1780
The “Withering-type Microscope” is named for its inventor, Dr. William Withering (1741-1799), an English physician and botanist who graduated with a degree in medicine 1766 in Edinburgh. Inspired by the taxonomical work and systematic classification of Carl Linnæus (1707-1778), Withering (1776) applied the Linnaean taxonomical system of classification to British plants in a seminal, two volume work, A Botanical arrangement of all the vegetables naturally growing in the British Isles. The earliest reference to a small botanical microscope of Withering’s design appeared in the first edition of this book. There, Withering indicated this microscope was developed for field dissections of flowers and other plant parts. While there is no surviving example of this exact design, close relatives of this type do exist, made either completely of brass or of ivory with brass pillars. Ivory models can be tentatively dated to 1776-1785, as by 1787 a newer model with a hollowed stage in an all-brass configuration already predominated. In turn, it was preceded by the brief appearance of a transitional brass model but with solid stage of ivory or horn (seen here). This version is extremely rare and must have been produced in very small numbers. By 1787 all these varieties were not recorded anymore in the literature.
References: SML: A242712; Goren 2014.
References: SML: A242712; Goren 2014.
Prof. Yuval Goren's Collection of the History of the Microscope
Benjamin Martin, Pocket Microscope (signed by Dollond), ~1770-80
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The term "field microscope" refers to a portable microscope intended for use outside of a laboratory. The definition of a laboratory has changed over time and now refers to a place where scientific research and analysis take place. In the past, the term "laboratory" was used to describe alchemists' workshops, and modern science labs as we know them today were not established until the 19th century.
The first classification of microscopes is between "simple" or "single" microscopes and "compound" microscopes. Single microscopes were designed to be portable and could be pocket-sized. There were various types, including optical compendia of different shapes, as well as "compass," "screw-barrel," "aquatic," and "botanical" microscopes. Specific types, such as the Lindsay, Watkins, and Clark pocket microscopes, were also included. Compound microscopes were quite complex and were not meant to be used in the field, although they could be transported in cases. So, just because an instrument is portable doesn't mean it's meant for fieldwork. Compound microscopes can be categorized as either benchtop or handheld, similar to the modern terms of desktop and portable as they relate to personal computers. In the 18th and 19th centuries, microscopes designed for use outdoors were often called "pocket microscopes." However, the best classification for field microscopes is compound microscopes that were intentionally designed and marketed for use outside of a laboratory.
In the book "The Young Gentleman and Lady's Philosophy" by Benjamin Martin, the character Cleonicus explains various types of microscopes to his sister Euphrosyne. When he mentions the pocket microscope, Euphrosyne questions whether a smaller microscope can do the same things as a larger one. In response, Cleonicus explains that the field of view is not always proportionate to the size of the instrument or glasses. He goes on to say that a compound microscope can be constructed to be as small as one inch in diameter and show objects almost as well as a larger microscope. To prove this point, Cleonicus provides a portable pocket microscope that can be used to view objects in the garden or field.
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Benjamin Martin (Gentleman's Magazine 1785)
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Martin's pocket microscope, second form, 1742
From: B. Martin, The Young Gentleman and Lady’s
Philosophy, 1772
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The production dates of Martin's Pocket and "Drum" microscopes are currently unknown, as well as the history of his work as a scientific instrument maker. The first pocket microscope was created while Martin lived in Chichester, and the improved shreen over pasteboard "drum" microscopes and brass models were produced during his time in London 1756 to 1782. Although Martin supplied Harvard College with scientific instruments in 1766, it's unclear whether the microscopes were produced by Martin or purchased from Adams and Nairne. However, there are a few anchors that can be used to determine the chronology of his microscope production during his 26 years in London, mostly from his dated sales catalogs and advertisements.
Turner (1981: 44-45) proposes that the early form of the microscope, made of lignum vitae, pasteboard, ray skin, and brass, traces its origins to around 1760. However, the all-brass microscope from a compendium is believed to have been produced around 1780 (ibid: Plate 3: 10, MHS 45432). Nevertheless, this dating might not be entirely accurate. According to Turner (ibid: 43), all types of microscopes, aside from the initial pocket microscope published in 1738 and subsequent models during Martin's time in Chichester, were manufactured during Martin's tenure in London, spanning from 1756 until his passing in February 1782. This indicates that Martin's production of pocket microscopes continued for 26 years. It is unclear whether the product lineup was consistent throughout this period, if different models emerged in a linear progression, or if multiple models were introduced simultaneously.
In the 18th century, there were numerous innovations and developments in microscopy. The drum microscope from that time has similarities to work by Benjamin Martin, although most of these microscopes are not signed. These similarities can be seen in the optical instruments advertised by Martin around 1750, known as the Cabinet of Optical Instruments. This type of microscope was often sold together with scioptic balls and telescopes. Even though one particular microscope is signed 'Dollond London', it is associated with Martin because there are no records indicating that the Dollond family produced a pocket microscope of this design before the end of the 18th century. Moreover, the Science Museum London houses a Universal microscope (SML 1925-148) that was likely made by Martin but signed "P et J Dollond Londres", possibly meant for export to France. It is known that Dollond put his name on instruments made by other manufacturers. The field lens between the Ramsden ocular in this microscope suggests that it was made after 1759.
© Microscope History all rights reserved. All photos are by Y. Goren under written permission of the Science Museum London, the Museum of the History of Science, Oxford, and the Whipple Museum, Cambridge, and from the Goren Collection.
After Martin's tragic death in 1782, it is believed that later models of his microscopes were signed by other makers. Following his death, his stock was auctioned off, and the auction sale catalog, held by the MHS, lists the instruments sold but unfortunately does not contain the buyers' names. This catalog, spanning five days starting on March 8th, 1782, indicates that the stock included around 40 microscopes of various types, including seven compound or double microscopes, several unfinished instruments, and a few others included in optical cabinets. Regrettably, the list with the buyers' names was destroyed during World War II due to the bombardments of Oxford.
During the 18th century, major retailers like George Adams Jr., Peter Dollond, John, William, and Samuel Jones purchased a significant amount of stock. They often signed their names on the unsigned instruments they bought and sold to solidify their investment. Many of these instruments were eventually acquired by John Jones & Son, who later became known as W. & S. Jones of Holborn. They advertised at least a dozen of Martin’s book titles in their catalogs, and many of the entries in their sales catalogs of instruments between 1787 and 1795 were directly copied from Martin’s. This suggests that John Jones and his son William were major purchasers at the Martin sales. However, it is also likely that other major instrument makers of the time, such as Dollond, Adams, Nairne & Blunt, attended the auction and acquired various numbers of Martin’s instruments, including some of his microscopes. As Martin apparently did not sign many of his brass microscopes, it was possible for these later acquirers to sign his old drum microscopes.
Reviewing Martin's Pocket Microscope
To determine if the Pocket Microscope truly matches the optical quality of the benchtop microscope from Martin's assertion, I conducted a comparison. I used a slide of scales from a butterfly's wings, which was commonly used in the 18th century to compare the resolution of microscopes. I compared the view seen under the pocket microscope with the view obtained under a contemporaneous double tripod ("Culpeper") type microscope from around 1770-80.
Seen below (from top to bottom) are three views of this slide: under Mertin's pocket microscope, under the bencotop double tripod microscope, and under a modern Zeiss Axioscope research microscope, all at approximately the same magnification.
The results support Benjamin Martin’s argument. Although the two 18th-century microscopes clearly suffer from pre-achromatic spherical and chromatic aberrations, the views demonstrate that their optical quality is not considerably different. The only difference could be found in the design and the ease and convenience of operation of the instrument. However, in the case of the double tripod (or Culpeper) microscopes, their design was very inconvenient, too, resulting from the need to maneuver the slide among the three legs surrounding the stage and look through the eyepiece directly from above without any possibility of tilting the instrument. Therefore, there was much logic and truth in Martin’s argument.
Benjamin Martin (attributed), Optical Cabinet, ~1760
Here we see a particular type of optical compendia, such as one found in several collections. Some examples signed by W & S Jones but many unsigned examples such as the one seen here are known. The telescopes are usually unsigned, in earlier versions (where the telescopes are coated with shagreen ond their draw-tubes are made of vellum-coated pasteboard), they are often signed by Martin or Dollond. But the pocket microscope and the scioptic ball appear to be produced by Martin. These compendia were stored in rough mahogany cases and sold to amateurish buyers.
In 2014, I studied Martin's pocket microscopes and copies of them in the collections of the Science Museum in London (SML), the Museum of the History of Science in Oxford (MHS), and the Whipple Museum in Cambridge. Photographs of these instruments were taken with permits and compiled into a group photo, highlighting the variability in forms that occur (see above). It seems that two of the instruments, Whipple 0588 and 1809, are not made by Martin, but all the other instruments can be traced back to him. The slight variations reflect the 18th-century practice of outsourcing the production of microscope parts between different workshops and only assembling and retailing them under the signature of the formal maker.
Martin used to attach his sales catalogues to the inside covers of some compendia. These catalogues contain valuable information, as mentioned by Millburn (1986b). Millburn organized the catalogues by year (1757, 1765, 1780) and arranged them based on their lists of items. the original prices can be restored.
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The scioptic ball is a mounting device for optical components. It consists of a wooden ball in a mounting frame. The ball can be oriented in any direction and then fixed in place with a retaining ring. Scioptic balls have been used in various ways, such as camera obscuras that project images from the outside on walls in darkened rooms or simply as light sources.
The scioptic ball was developed by Daniel Schwenter in 1636. Later, in 1685, Johannes Zahn illustrated a large workshop camera obscura for solar observations using the telescope and scioptic ball. However, one disadvantage of this device was that as the earth rotated, the sun's apparent position changed in the sky, and the ball had to be moved to follow it, causing the location of the image inside the room to change as well. For a substantial part of the day, the image had to be projected onto the floor.
Around 1700, some workers apparently used a separate mirror to reflect the sun's rays into the projection device, but this required an attendant outside the projection room as it was very difficult and inconvenient to accomplish. It was later that Fahrenheit integrated a mirror and a projection device, producing the first practical solar microscope.
Benjamin Martin attached a mirror to his "Scioptic Ball," but this was not an improvement on Fahrenheit's design. It was John Cuff who first invented a Solar Microscope in which the optical tube remained stationary, and the mirror moved, controlled from inside the room.
Early models used a push-and-pull mechanism to adjust the mirror using levers, but starting in the last quarter of the 18th century, geared adjustment became the usual. This arrangement continued for at least the next century, and this type of Solar Microscope was made by many well-known later 18th to early 19th-century makers.
Most solar microscopes until 1774 were designed to show only transparent objects, but in that year, Benjamin Martin announced his newly constructed 'Opake Solar Microscope' which used a mirror box to project the image of an opaque subject. Opaque solar microscopes are rather rare today, and few collectors possess one.
At the same time, Martin marketed scioptic balls as part of his "optical cabinets," which were popular optical compendia containing a pocket microscope, a basic form of telescope, a screw-barrel microscope, and a mahogany scioptic ball. These sets were not intended for professionals or wealthy amateurs, but they were, in fact, quite effective and were marketed in significant numbers. Many probably remained in Martin’s stock, as evidenced by the above-mentioned auction list, and were marketed by other makers, sometimes having their names printed on paper and glued to the inner part of the case cover.
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Similar instruments are in SML: 1925-148; A124818, 1911-295, 1928-919, A645009, (compendia by Benjamin Martin); MHS 98894, Golub: 260 (unsigned compendium); Whipple: 588, 1809; Boerhaave: V07433; Clay & Court 1932, Fig. 128; Sotheby’s Dec 2006 cat. (signed B. Martin); Gemmary CD Cat. 23, 2004; Tesseract Cat. 95, 2012; Turner 1981: 44 (right); Skinner 1997: 91.
References:
Millburn, J., 1976. Benjamin Martin, Author, Instrument-Maker and 'Country Showman'. Leyden: Noordhoff International Publishing.
Millburn, J., 1986b. Retailer of the Sciences, Benjamin Martin's Scientific Instrument Catalogues, 1756-1782. London: Vade-Mecum Press.