Benjamin Martin and His Visual Glasses

+ Larger Font | - Smaller Font

Certainly one of the most distinctive styles of eyeglasses ever created were Benjamin Martin’s “Visual Glasses”, the so-called “Martin’s Margins” (the collector’s term). A style first introduced in the second half of the 18th century they are not common yet they are indeed quite unusual and are therefore desirable and popular among all collectors. Many museum collections have an example or two. Unique in their appearance, they deserve a dedicated page on this website explaining their interesting story.

Adapted mostly from a paper presented at the May 14th 2004 Ocular Heritage Society meeting in Chicago, Il. by Charles E. Letocha, M.D.


Benjamin Martin, noted eighteenth century English instrument maker, had a significant influence on the development of numerous optical instruments including spectacles. Born in Surrey (at Chichester) in 1704, he started his career as a schoolmaster and later published books on microscopy and mathematics. Eventually he opened a shop (in early 1756) on Fleet Street in London where he developed his scientific instruments.

Visual Glasses

His shop was located near the entrance to the Royal Society and members approaching that building would have had to pass near his place of work. Martin’s building was identified by his sign - Visual Glasses and a Globe. He began selling visual glasses as soon as he moved to London, although the earliest advertisement found thus far is from July, 1756. Scientific instrument makers did not have a guild of their own and they were free to join any guild; surprisingly, many were members of the Grocers Company, but Martin joined the Goldsmiths Company. There is strong circumstantial evidence that Martin did not actually make the articles he sold in his shop, including visual glasses. Rather, he had a few workers in the shop and also subcontracted some work to various journeymen around London.

For historians, Martin issued a booklet explaining visual glasses with each pair he sold. Published initially in 1756, it was then reprinted four times until 1760. Martin devised visual glasses as a result of his own presbyopia. He listed several problems with “common spectacles”:

1. the glasses are placed in the same plane, rather than converging toward the object of regard.
2. that angle causes the rays of light to be refracted irregularly toward the eye.
3. cumulative light exposure is harmful to the eye and it admits three times as much light as is necessary for clear vision.
4. a particular quantity of light is proper for perfect & distinct vision; common spectacles impair and confuse the image.
5. the large lens size permits irregular refraction from the periphery of the lens.
6. red light is composed of the largest sized particles and blue the smallest. Common spectacles of clear glass or colors such as green admit the larger sized particles that are not as refractable as the smaller particles
7. the image through a properly colored lens is more perfect than through a clear one.

His solution to these problems was “Visual Glasses” whose properties included the following:

1. the lenses were tilted inward toward the object of regard. The purpose was to have the refraction occur through the center of the lens more so than the periphery.
2. the lens was reduced from a diameter of 1½ inches to about 1 inch by an annulus of horn. This lens admitted 1/3 the amount of light of a standard one.
3. the lenses were colored blue or violet (he considered this color least hurtful to the eyes) mostly , rather than being clear or green

Martin advertised his new invention regularly throughout 1756 and into 1757. That, combined with the lectures he gave on a regular basis, created anger and consternation among other opticians and scientific instrument makers, many of whom had shops near his.

Advertising Battles

In the latter half of 1756, there was a running battle between Martin’s advertising his visual glasses (or, as he called them in one ad, “Philosophical Spectacles”) and the reaction by James Ayscough, another prominent optician (famous for the “double hinge” 1752). On September 22, Martin ran an ad extolling their virtues: “constructed on the genuine principles of optics for preserving the eyes, and rendering vision the most easy and distinct that is possible.

On October 19, Ayscough placed an advertisement stating: “the public have been amused with several advertisements relating to visual glasses, the author of which pretends to be the inventor, and would endeavor to persuade the public he has more knowledge than any of the optical trade, and farther has presumed to threaten those who shall oppose him, I therefore dare to tell him, that it is an imposition, and that he never invented any visual glass whatsoever; and I further declare, that the spectacles he sells under that denomination, are made of the most inferior kind of glass, and defy him to prove the contrary.”

An anonymous ad 2 weeks later was a bit more tongue-in-cheek. Ayscough then demanded a reply to his accusations but Martin never did so. In apparent exasperation, he placed a long, final advertisement on December 6. “The public have been amused with several advertisements relating to Visual Glasses, the author of which pretends to be the inventor, (although these things were made by me, and others occasionally, many years ago) and have still the assurance to insinuate to the public, he has more knowledge than any of the optical trade, and has presumed to threaten those who shall oppose him. I dare to tell him it is an imposition, and that he never invented any visual glass whatsoever; and I further declare, that the spectacles he sells under that denomination, are of the most inferior kind of glass, particularly that sort recommended in his essay. Since therefore that Visual Advertiser has not thought proper to answer my former advertisements, nor modest enough to desist from his own, I am (tho’ I detest advertising) laid under an obligation in just defense of myself and brother traders from being injured in our natural right, and the public in general farther deceived, thus openly to call on the author to lay aside all mean artifices., and new coin’d expressions. Ayscough continued his criticisms of Martin: “as [Martin’s] pamphlet is so productive of quackery and ignorance, my friends thought it absolutely necessary I should make some few remarks thereon, not only in vindication of myself and others, but also to prevent the public being imposed on. I shall make no observations on his former works, compiled only from the better authors, than that they would pass tolerably well, were the errors corrected by some more judicious person. The few remarks to be made shall be very concise: but whether to laugh at his ignorance, or be angry at his impudence, is what I am at a loss about, therefore shall leave that to those who read this pamphlet. Martin sells spectacles made of the most inferior kind of glass, namely, the white flint; which is fuller of veins and specks than any other, except that which he recommends.”


Apparently, Martin was an energetic and gifted retailer and self-publicist and his visual glasses were popular immediately. This was probably one of the sources of consternation to the established London opticians. Some of them began copying the Martin form. In the Essay on Visual Glasses, Martin commented “those who weakly insinuate that I imitate them, must be told, that they publish an untruth; I have no reason for doing that; their inventions are too mean and unscientifical to deserve my notice: I sell little besides what I have contrived myself; and my instruments will recommend themselves to all judges of science; and not only that, but save the public cent. per cent. in buying. I have only one favour to ask these worthy gentlemen, and that is, that, since they have taken so much pain to depreciate my inventions, they will act consistent with themselves and not imitate them. Let them who know nothing of optics, make spectacles; and those, who profess not to use their reason, buy them; I shall always find a demand for VISUAL GLASSES. In a 1757 broadside: “every sort of visual glasses of my make are marked with the initial letter of my name (B.M.). Of some interest, then, is a price list from 1762 and others of later years, in which Martin says: “N.B. the Visual Glasses sold by peddlers, Jews, &c. with the initial of my name, were never made or sold by me.” This presents an interesting dilemma to the collector of spectacles: are the ones marked “B.M.” genuine or made by his competitors? Clearly, they could be either. So much piracy of the “B.M.” mark occurred that there were probably more copies than Martin originals available and he was better off not placing the mark.

Criticisms and responses to them

Criticisms of visual glasses must have occurred immediately or were anticipated by Martin because he gave responses to them in his Essay.

1. A customer said he could not see better to read with them, or find them easier on the eyes than common spectacles. Martin’s response was that a response should not be noted immediately but only after having worn them for a sufficient period of time.

2. Another customer said that he did not find the light to hurt his eyes any more with common spectacles than with visual glasses. Martin’s response was similar in that the benefit would accrue in the future, not immediately upon using them.

3. Visual glasses have an uncouth look. Martin’s answer: “ a judicious person, whatever is best, has the best look; and they sit most properly in that position which nature has directed.”

4. They are more expensive than regular spectacles. Martin’s reply: “nor are they dearer than the common sort, viz, from 2s.6d to 5s.6d and the best temple visuals with pebbles at 18s a pair.” An advantage that Martin did not specify himself is that they might have reduced the price of spectacles made of pebbles by reducing the size of the lens needed. Pebble spectacles were significantly more expensive than ones made with glass lenses.

Visual Glasses in America

A 1766 letter from Virginia to England includes a postscript: “Mrs. Nelson begs you to send her a pr. of Mr. Martin’s visual glasses for one of 48 or 49 years old.” Advertisements can be found for Gararous Duyckinck in the New-York Mercury of October 6, 1766, for James Craig in the Virginia Gazette of April 7, 1768 (“just imported from London...some fine visual spectacles, fit for all ages”) and for John Greenhow in the Virginia Gazette of April 11, 1771 (“visual spectacles, of a new construction, by Martin, the celebrated optician”)

The spectacles of Abraham Redwood (1709-1788) still reside in the Redwood Library and Athenaeum in Newport, Rhode Island. Unfortunately, there is no record of when he purchased them or from whom.

A pair of spectacles with tortoiseshell annuli and marked E. Hughes is in the collection of Yale University Art Gallery. An image of these is not being made available but this pair dates to the 1820-30's.. A second pair, marked Deamer, is at the Fairfield (CT) Historical Society. Whether these were actually made by Hughes and Deamer is, of course, speculative. It is possible that old “visual horns” were placed into those marked frames at a later date or that a customer might have wanted old “visuals” in a new frame when Hughes and Deamer were working.

How long were Visual Glasses available?

The auction of Martin’s shop and its contents in 1782 included over 500 pairs of spectacles, half of which were visual glasses. His employee, Gabriel Wright, went to 148 Leadenhall Street to join Henry Gregory; a trade card issued by Gregory & Wright shortly afterwards had a representation of reduced-aperture spectacles in one corner, with the caption “Visual Glasses by G. Wright from Mr. Martin’s, Fleet Street”.

George Adams, in An Essay on Vision, 1789 commented about visual glasses: “But the good sense of the world, which always, in the long run, justly appreciates the value of every invention, now leaves visual spectacles to the neglect they merit; they are worn by few, but those who, from long habit, have accustomed their eyes to these pernicious shades.”

In his 1793 catalogue, J. Bidstrup included “spectacles with visual horns”. William and Samuel Jones included “spectacles with Martin’s visual horns” at the same price as other spectacles with the same frames in their catalogue of 1793. William Jones had been an apprentice with Martin. Others included David Jones (who ran away from Martin), and Gabriel Wright (mentioned above).

They are seen in portraits painted in 1796, 1805, and 1824, as well as an undated child’s riddle book, The Puzzling Cap (probably late 18th century). There are marked European examples made of silver from the first quarter of the 19th century, which are quite unusual. One unique solid gold pair belonged to King Louis 15th and another gold-plated pair is at the Museum of Vision in San Francisco.

Victorian-era frames with Martin-style margins of horn or, more commonly, tortoise shell can be found. Almost all of these have very high plus power lenses that probably were intended for aphakes. These were devices created to reduce peripheral aberrations from these strongly convex lenses, rather than true “visual glasses”. Despite their being relatively prevalent in modern collections, no description of them has been located in texts or catalogues of the late 19th century.

“Martin’s Margins”

The term “Martin’s Martins” is commonly used by collectors but no one seems to know who invented the term or when. Clearly it was not used when visual glasses were actually being used and probably dates back no more than 30 years or so. Therefore one should probably consider it a collector’s term.

Related devices?

There are late 18th to early 19th century spectacles that have frosted rims, usually in the shape of a square or diamond. Most of the ones seen do have some power, usually in the range of 2-4 diopters. No primary references to these lenses have ever been located nor has a compelling explanation of the purpose of the frosted periphery been given. Did the frosted area serve a function analogous to the annulus of visual glasses?

Charles Jachan holds an 1839 American patent (#1130) for a similar lens. “The object of my invention is to protect the eye from too strong a light as much as possible, and this I effect by leaving only a small portion of the surface of the glasses polished and surrounding it with a ground space extending to the circumference or outside rim, intended to obstruct the passage of the rays of light and soften their effect upon the eye, leaving that portion opposite the pupil a small clear circular space.”


Although a modern analysis of Martin’s theory for visual glasses would probably concur with his detractors, he certainly has provided present day collectors with a style that is much desired. It is interesting to note how many specimens have survived 200+ years. Are they so curious in appearance that people have not discarded them? Were they better-constructed than other contemporary spectacles and, therefore, lasted longer? Or, were they very popular, with the opportunity for many to survive?
In conclusion because of his many contributions Benjamin Martin is considered to be one the greatest designers and manufacturers of microscopes and spectacles of his time. It should be noted that a large group of instruments supplied by Martin are still extant at Harvard College, having been acquired during 1765-1768 with the assistance of Benjamin Franklin.

Important Chronology

1704 Born
1737 Founded a literary library
1749 Published an English Dictionary
1756 Probably moved to Fleet Street, London
1756 Published his first booklet describing his Visual Glasses
1776 Retired from active business
1782 Was declared bankrupt, tried to commit suicide then died shortly afterwards

His invention was his shop sign and also his personal symbol.

John R. Millburn has published 3 books on this subject

  1. Millburn JR. Benjamin Martin. Author, Instrument-maker, and ‘Country Showman’. Leyden: Noordhoff International Publishing, 1976.
  2. Millburn JR. Benjamin Martin. Author, Instrument-maker, and ‘Country Showman’. Supplement. London: Vade-Mecum Press, 1986.
  3. Millburn JR. Retailer of the Sciences. Benjamin Martin’s Scientific Instrument Catalogues, 1756-1782. London: Vade-Mecum Press, 1986.

Home ] Introduction & News ] History & References ] Identification & Preservation ] Public Collections & Virtual Museum ] Interesting Topics ] Education & Games ] Links ] About Us ]