Robert George Mason, 1849 - 1912

by Brian Stevenson
last updated July, 2021

R.G. Mason was a professional microscope manufacturer and preparer of microscope slides during the last decades of the 19th century, continuing into the early years of the 20th. Around the year 1880, Mason quit his job with the Swift optical works and began his own business. That venture lasted until about 1900. Mason continued to produce both prepared slides and unmounted specimens until his death.

Mason’s slides were consistently well made, and included a wide variety of specimen types (Figure 1). His slides include some highly artistic preparations, aesthetically pleasing on both microscopic and macroscopic scales. For example, the second slide in Figure 1: a single leaf, retaining its color, dry-mounted against a black background and centered within concentric rings of the same colors. He even used color-matched labels.

Figure 1. Examples of microscope slides produced by R.G. Mason. His custom-made name labels are small and separate from the off-the-shelf specimen identification labels, likely to save production costs. As a result, many owners have removed Mason’s identifying label. He lived on Park Road, Clapham from 1881 until ca. 1909. The section of Primula cashmeriana leaf in the leftmost slide is still vibrantly colored, even after 120 years. The label references the textbook ‘Natural History of Plants’, by Anton Kerner von Marilaun and translated into English by Francis W. Oliver in 1895. The beautifully-mounted leaf next to it is from an African herb now known as Dicerocaryum zanguebarica. Mason extensively advertised his preparations of limestone from Llanynynech, Montgomeryshire, Wales at the turn of the 20th century.


Figure 2. A botanical microscope slide labeled by both R.G. Mason and The Morphological Laboratory, which was a London partnership between John E. Ady and Heinrich Hensoldt during 1883-1884. Arthur Doherty also had a brief partnership with Ady at that same time. As Doherty was highly skilled at preparing slides of stained botanical sections, this may have been his work. Most likely, Mason added his trade label for re-sale. The address of 24 Park Road, Clapham, dates his possession of the slide to between 1883 and ca. 1890. A similar Morphological Laboratory slide with a Mason label is illustrated in Bracegirdle’s Microscopical Mounts and Mounters, Plate 25-J.


Mason’s microscope manufacturing and slide making business was a small affair, with him as the only known employee. The 1891 census listed Robert Mason as being “neither employed nor employer”. Strikingly, his 15 year-old son was recorded as being “employed” as an “optician’s assistant”. If accurate, then the son was working for another optician, probably as an apprentice.

His advertisements indicated that Mason’s business began in 1880. The 1881 census listed him as then being an “unemployed optician”, suggesting that he was still working to get his business going. While he presumably produced microscopes during the 1880s, I did not find any records of what they were like. However, he was variously described as being a “manufacturing optician to the trade” and “a trade maker”, so he may have been primarily a maker of unlabeled microscopes that were sold by other retailers.

Mason made a big splash in 1890, with the release of a hybrid microscope that functioned as a standard table instrument and could also be connected to a light source for use as a magnifying projector (Figures 3 and 4). The concept was not new, but Mason’s ingenious model was constructed such that nothing needed to be disassembled for the transition – one simply swung the base out of the way and attached the condenser to a light projector. This invention won him a Silver Medal at the 1893 Exhibition of the Royal Cornwall Polytechnic Society. Despite extensive advertising and published high praises, Mason’s output appears to have been fairly small and I have not located any evidence of surviving microscope-lanterns. However, London’s Museum of the History of Science has a projection microscope that was made by Mason (Figure 5).

Figure 3. As described by the Journal of the Royal Microscopical Society in 1891, “Mr. R. G. Mason, of 69, Clapham Park Road, Clapham, S.W., has introduced the above form of lantern and table Microscope, a patent for which has been applied for. Until the present time the lantern Microscope has been a distinct instrument from the table form of stand. By the union of the above parts an instrument is obtained that, when not in use for screen projections, can be easily altered, as shown by fig. (2). No unscrewing is required, and there are no loose parts. Fig. (1) shows the instrument as used on the lantern. It is very convenient for the science teacher or general lecturer, as a demonstration may be made to either a small or large audience with equal facility. The lower part, which carries the joint for inclining the instrument at any angle, is fitted with concave and flat mirrors on swinging arm, also with the universal size substage fitting tube for apparatus. The body and draw, which fits into the upper part, is of large diameter, and is screwed with the Society's size screw, thus enabling any ordinary microscopic objective to be used with it. It is fitted with a first-class rack, and also screw fine motion working steadily under high powers. This fine motion is especially useful in photomicrography. The stage being of the usual form, both object and objective are in view, and easily manipulated while in use, thus doing away with an objection that is often present in the older forms of lantern Microscope. A further improvement is a spring clip, enabling the object to be easily changed without scratching the labels, &c., its construction admitting of either a deep zoophyte trough or the thinnest 3x1 slip being held gently but firmly. The parts are supplied separately, so that any one needing only the lantern arrangement can add the other at any future time”.


Figure 4. Advertisement from the July, 1893 issue of Hardwicke’s Science-Gossip.


Figure 5. A simple projection microscope by R.G. Mason. Image from the Museum of the History of Science, used for non-profit, educational purposes in accordance with Creative Commons understandings.


In Victorian times, the term “optician” was applied to any worker involved with optical devices, including microscopes. The two major ingredients of a microscope are brass and glass, and Robert Mason’s early training made him an expert in brass.

His father, Robert William Mason, worked in the gun-making trades as a finish polisher. He was evidently quite successful at that occupation, as the family retained live-in servants. Robert George Mason was the first child, born during 1849 in the Whitechapel area of London. His mother died in 1856, possibly as a consequence of giving birth to the family’s fourth child.

The 1871 census found Robert George boarding with a gunsmith in Enfield. Most of their neighbors were also involved with gun-making, although one man next door was a sword-maker. Robert, however, was an “optician”, possibly working for a nearby telescope or microscope manufacturer.

In addition to Robert’s upbringing, his later writing and advertisements indicate strong, practical knowledge of brass and iron work. Figure 6 illustrates advertisements from Mason in which he offered unfinished brass parts such that enterprising people could build their own microscopes, offered advice on assembling/repairing a key microscope component, and applied for a metalworking lathe. In addition, he published advice on giving brass a black finish, coating a mirror with mercury and silver, soldering gun-metal, case-hardening iron and many other aspects of metalworking.

Figure 6. Advertisements and helpful tips from R.G. Mason, indicating his experience with brass working and microscope construction. All from The English Mechanic and World of Science.


Mason married in 1875, again describing his occupation as “optician”. At that time, he was living in Brighton, while his wife, Elizabeth, was from London. Mason then moved to the London area. Since Mason worked for Swift, they probably lived near that factory, which was on Tottenham Court. Mason stated that he left Swift to begin his own business in 1880. He set up the family household and his business in the same building, on Clapham Park Road, south of the Thames. Mason remained on that road until near his death, occupying four different buildings: number 28 from 1881 to 1882, number 38 from 1882 to 1883, number 24 from 1883 to ca. 1890, and number 69 from ca. 1890 to ca. 1909.

Figure 7. Advertisements spanning Robert Mason’s career as a professional maker of microscopes and microscope slides. His microscope manufacturing business operated from 1880 until around 1900. The first records of his slide-making are from 1882, and extend until just before he died.


Published advertisements indicate that Mason sought to expand his microscope-making business in 1882, to include specimens for slide-making (Figure 7). During that year, he posted twice in the popular magazine Hardwicke’s Science-Gossip, offering unmounted foraminifera and other objects in exchange for “interesting objects”. This was a common means for slide-makers to diversify the types of objects they could offer to customers.

Advertisements from throughout Mason’s career indicate that the primary focus of his slide business was prepared, but unmounted, specimens. These were sold to amateurs, and possibly other professionals, so they could make their own slides with high-quality specimens. Mason’s first known specimens for mounting were sections of lungs and other anatomical objects. These would have been reasonably easy to mass-produce for a person with a decent microtome. A piece of lung or kidney from the butcher’s shop would make a lot of specimens. Some of the specimens were reported to be human, which could be acquired from morticians, hospitals, doctors or medical students.

An 1883 advertisement offered a collection of pathology and anatomy slides “from the collection of an M.D.” (Figure 7). Reselling used slides was a simple source of income, and a widespread practice among professional slide-makers.

Advertisements from as early as 1882 state that Mason included “instructions for mounting” with his specimens, suggesting that he knew what he was doing in that department. Within a few years, he began offering completed, prepared microscope slides. Circa 1891, he published a pamphlet entitled Practical Hints on Mounting.

In addition, Mason was a frequent contributor to magazines such as The English Mechanic and World of Science, offering tips on various aspects of microscopy and metalworking. For examples, from 1891:

The best method to obtain cuticles of leaves is by soaking the leaf in soft water (rain-water). Time will vary very much, according to specimen; hard specimens, such as Hoya carnosa, may take a month or longer. When specimen appears to be soaked enough, take one out and try with a needle at the base of leaf; if cuticle comes up readily go on (if not, again immerse). Gently clear it at the extreme edge. Now lay it flat on a three by one slip, and with a pair of forceps gently put it up towards the tip. Hold the lower portion of the leaf on to the glass with a needle or forceps. As soon as you have got cuticle off, place in clean water, brush with a camel-hair pencil; if required stained, and colour is bad, bleach in chlorinated soda solution; stain with aniline or logwood, and mount in the usual way - balsam or glycerine. R.G. Mason, Manufacturing Optician, 69, Park-road, Clapham, S.W.

You will not find mounting the moth antenna dry a very satisfactory way. It can be done in a shallow cell; but if you clean it of dust, and soak it in spirits of turpentine for say 24 hours, you will find this will not hurt it, and you can then mount in Balsam and benzole, or you may take it fresh from the insect and mount it in glycerine in a cell, seal the cell with Miller's cement: no difficulty then in keeping it air-tight. There is no way, I believe, to show the wheel of animalcula, excepting when they are living. Arrange your insects on a glass slip, put paper or card to about the thickness, place another slip on, put indiarubber band round, soak in alcohol 24 hours, then clove oil, then mount in balsam and benzole. Only patience and perseverance will overcome the legs, &c., moving; try again—it will come right by. R.G. Mason, Manufacturing Optician, 69, Park-road, Clapham, S.W.

There is no society or club specially for a beginner in microscopy; but if you will write me to say the part of London that will suit you best, I will endeavour to tell you the nearest micro club. You will find all beginners will have a hearty welcome in most clubs. French objectives are of no use for photomicrography, unless specially constructed for the purpose. Those supplied with students' microscopes are certainly of no use. A rack and pinion - that is, a good one (not the average rack and pinion supplied with the £3 3s.) - is not exactly a necessity; but you can get on much better with one than without: it makes manipulation easier. The most useful powers for a beginner are a 2 in, 1 in., and 1/2 in. - only get good ones. R.G. Mason, Manufacturing Optician, 69, Park-road, Clapham, S.W.

Evidence suggests that, by the early 1890s, Mason had acquired skills for grinding optical lenses. He published a 12 page booklet entitled Do I Require Spectacles? in 1891. Also that year, he offered this advice in The English Mechanic and World of Science, “Ophthalmic. - Your Son has some defect in the refractive media of the eye, no doubt. Take him at once to a good oculist; ordinary medical men do not as a rule make the eye a speciality (some do). It must be seen to quickly, or a permanent squint will be the result; in all probability, he will always have to wear spectacles. R.G. Mason, Practical Optician, 69, Clapham Park-road, Clapham, S.W.”. That was an obvious advertisement, projecting competence in matters of the eye, providing his address and describing himself as a “practical optician”. Microscope lenses with Mason’s name were presumably made by him (Figure 8).

Figure 8. A microscope objective lens and canister, labeled by R.G. Mason. Image courtesy of William Roy Gibson.


As with so many other people of his era, Mason developed a strong interest in photography. He combined his expertise with the microscope and camera to make photomicrographs, and from them, lantern slides. Two examples of these many interests are 1896 reports from the Brixton and Clapham Camera Club (of which Mason was the Club Lanternist), “An Hour with the Lantern Microscope, by Mr. R.G. Mason .. The Club does not always devote its meetings to strictly photographic matters, such as the action of developers and toning baths, or even to ‘Art with a big A’, but occasionally gets out of the usual routine with a fixture like the present. Mr. Mason's demonstration was really a natural history lecture, numerous mounted microscopical specimens of the insect and vegetable world being projected on the screen, and their peculiarities described. This was followed by living specimens taken from ponds in the locality, Mr. Mason remarking that the ‘improvements’ of the County Council made his subjects increasingly difficult to find. However, he had got together a good selection of water-mites, water-fleas, and other aquatic insects, the most interesting exhibits, perhaps, being the circulation of blood as shown in the leg of a frog, and the water-hydra stretching out its tentacles to capture its prey, and afterwards devouring the same, an exhibit so realistic as to produce cries of ‘Shame’ from a somewhat susceptible member of the audience. In conclusion, Mr. Mason received cordial thanks for demonstrating a branch of science so inviting in its photographic possibilities”, and “At a recent meeting Mr. R.G. Mason read the following paper on ‘Elementary Photo-micrography’: In introducing this subject to your notice, I do so with the feeling that it is at present a very limited branch of photography, but in these days of scientific research there seem to be very few processes of manufacture in which directly, or indirectly, the camera or the microscope are not used. The use of the camera in conjunction with the microscope is most useful for teaching purposes, a method whereby a faithful image of almost any specimen it is possible to view may be permanently secured, and used as a diagram or the more popular lantern slide. The only previous method of copying microscopic specimens was to draw them, either by means of the camera-lucida, or by looking into the microscope, and then trusting to memory and skill with the pencil and brush. Some very beautiful work has been done in this way; but however carefully a subject may be drawn, it can never present all the detail of a good photograph of the same object. The question may arise, ‘What is the good of a photomicrograph when obtained to anyone not a lecturer or teacher’. I can only answer, Very little, if you are not a lover of nature as revealed by the microscope; but if your taste does lie in that direction. I can promise that you will have a most fascinating branch of photography, one that you can pursue in any weather, independent of even daylight. For elementary work with objectives ranging from 3 in. to 1 in. - these will do almost any average work - the expense need not be great. A £5 note and a little home-made apparatus will set any ordinary person up in that direction .. ”.

Figure 9. The merging of Mason’s interests in microscopy and photography. Advertisement from ‘Nature’, 1905.


Robert Mason was still manufacturing microscopes of his own design in 1899. That year, Hardwicke’s Science-Gossip reported, “Mr. R.G. Mason, of 69, Clapham Park Road, sends us an interesting list, which contains several novelties, amongst which we may mention a convertible lantern and table microscope. Most of the microscopes appear to be of good design, and there is a new model specially designed for the use of teachers, which is called ‘The Champion’, concerning which we can speak favourably after a personal inspection. It is on a tripod form of foot, has diagonal rack coarse adjustment, and lever fine adjustment, draw-tube, sub-stage tube for condenser, and the usual mirrors. The workmanship is sound and the price of the stand alone is only £3 13s. 6d. We may also call attention to Mr. Mason's sets of mounted slides for students, and lantern slides for lecturers, specimens of which have been submitted to us, and which are both good and reasonable in price. Beginners will find the various series of prepared but unmounted objects excellent practice, and we note with approbation that these have been, in each case, sent out still moist from the final clearing stage”.

However, the 1901 English census listed Mason as being a “worker”, rather than employer or self-employed, indicating that he had returned to working for another optical business.

As noted above, Mason continued to produce slides and slide material until near the time of his death. In 1906, Knowledge and Scientific News reported, “Mr. R.G. Mason, of 69, Clapham Park Road, S.W., sends me specimens of a series of interesting objects ready prepared for mounting, or requiring only soaking in spirits of turpentine beforehand. These are very suitable for beginners, and others would do well to obtain the list and peruse it, as by obtaining some of these sections they can, with a minimum of trouble and expense, add many interesting slides to their cabinets. Many of the botanical sections are double stained, nearly all are arranged in typical sets, and the cost only averages from one penny to three halfpence per slide. Full directions for mounting are sent with each series. Mr. Mason also sends me specimens of completely mounted objects, amongst which I may mention a fine section of limestone from Llanymynéch showing unusually perfect fossil remains”.

Around 1909, Mason, his wife and 3 of their unmarried children moved from Clapham to 78 Foxbourne Road, in the Upper Tooting area of London. Robert died on April 3, 1912, at the age of 62.

Figure 10. Advertisements from the 1895, second edition of Arthur C. Cole’s ‘Methods of Microscopical Research’


Figure 11. Mason's "Histological and Botanists' Microscope", circa 1895 (see Figure 10). Adapted for nonprofit, educational purposes from an internet auction site.


Figure 12. Compound and simple dissecting microscope by R.G. Mason, circa 1890. Adapted for nonprofit, educational purposes from an internet auction site.


Figure 13. Circa 1910 photograph of R.G. Mason and his family. The adults are (from left to right) Robert's wife, Elizabeth, son Joseph Bromley Mason, Joseph's wife, Ellen, and Robert. The three children are the daughters and son of Joseph and Ellen. Image generously provided by R.G. Mason's great-grandaughter, Lindsay Groom.



Many thanks to Lindsay Groom and William Roy Gibson for their generosity in providing images for this essay.



Bracegirdle, Brian (1998) Microscopical Mounts and Mounters, Quekett Microscopical Club, London, pages 65 and 154, plate 25 slides J and K (K was prepared by Mason, J was produced by the Morphological Laboratory and carries Mason’s address label, probably a resale)

Cole, Arthur C. (1895) The Methods of Microscopical Research, second edition, advertisements from R.G. Mason at rear of the book

Cornwall Polytechnic Society Annual Report (1893) Descriptions of prizes awarded at exhibition: Lantern and table microscope, R.G. Mason, Second Silver Medal, “In microscopes some perfectly finished and most admirable instruments and devices were shown by Mr. Mason, of Clapham, whose arrangements for combined use in his oxy-hydrogen lantern and table microscopes are unrivalled in handiness, excellence, and efficiency. There are two forms, one being specially adapted to take the large photographic astronomical slides. The end attained is the same in both, namely, the provision of an instrument which can be used to demonstrate before a large audience, while when it is not in use in that way it is easily convertible into an ordinary form of table stand, the lantern fitting being slid off and another stand and body substituted”, pages 46-48

England birth, marriage, and death records, accessed through

English Mechanic and World of Science (1882) Sixpenny Sale advertisements from R.G. Mason, Vol. 36, November 24 and December 1 issues

English Mechanic and World of Science (1883) Sixpenny Sale advertisements from R.G. Mason, Vol. 36, pages 466, 512, 536 and 604

English Mechanic and World of Science (1883) Sixpenny Sale advertisements from R.G. Mason, Vol. 37, pages 44, 118, 140, 302 and 350

English Mechanic and World of Science (1883) Sixpenny Sale advertisement from R.G. Mason, Vol. 38, November 23 issue

English Mechanic and World of Science (1892) Sixpenny Sale advertisements from R.G. Mason, Vol. 54, page 452

Gill, Steve (2008) The Adye enigma, Quekett Journal of Microscopy, Vol. 40, pages 685-694

Gill, Steve (2009) The Ady(e) enigma - resolved, Quekett Journal of Microscopy, Vol. 41, pages 121-131

Hardwicke’s Science-Gossip (1882) Exchange offers from R.G. Mason, Vol. 18, pages 72 and 96

Hardwicke’s Science-Gossip (1883) Editor’s note on anatomical objects offered by R.G. Mason, Vol. 19, page 66

Hardwicke’s Science-Gossip (1883) Advertisement by R.G. Mason, Vol. 20, January issue, page vi

Hardwicke’s Science-Gossip (1886) Exchange offers from R.G. Mason, Vol. 22, pages 72, 95 and 144

Hardwicke’s Science-Gossip (1889) Exchange offers from R.G. Mason, Vol. 25, pages 24 and 95

Hardwicke’s Science-Gossip (1891) Advertisements by R.G. Mason, Vol. 27, pages xciv and lxxviii

Hardwicke’s Science-Gossip (1899) Editor’s note on Mr. R.G. Mason’s catalogue, Series 2, Vol. 6, page 248

Hardwicke’s Science-Gossip (1900) Editor’s note on Mason’s section of limestone slides, Series 2, Vol. 7, page 28

Hardwicke’s Science-Gossip (1901) Advertisement by R.G. Mason, Series 2, Vol. 8, page 192

Hardwicke’s Science-Gossip (1902) Advertisement by R.G. Mason, Series 2, Vol. 8, inside cover of March issue and elsewhere

Journal of Microscopy and Natural Science (1891) Mason's improved oxyhydrogen lantern and table microscope, Vol. 10, pages 119-121

Journal of the Royal Microscopical Society (1891) Mason's improvements in oxy-hydrogen microscopes, pages 89-90

Kelly’s Directory of Chemists and Druggists (1885) Microscope Manufacturers .. Mason Robert George, 24 Clapham park rd sw, Fifth edition, page 350

Knowledge (1910) Advertisement from R.G. Mason, Vol. 33, December issue inside front cover

Knowledge (1911) Advertisement from R.G. Mason, Vol. 34, page 498

Knowledge and Scientific News (1906) Editor’s note on Mason’s slides and specimens for mounting, New series, Vol. 3, page 337

Knowledge and Scientific News (1908) Advertisement by R.G. Mason, New series, Vol. 5, page xii

Marriage record of Robert George Mason and Elizabeth Mary Lugger (1875) Poplar All Saints parish records

Mason, Robert G. (1891) Ebonising brass, English Mechanic and World of Science, Vol. 53, page 210

Mason, Robert G. (1891) Spoiled brass, English Mechanic and World of Science, Vol. 53, page 211

Mason, Robert G. (1891) Cement for fresh-water aquarium, English Mechanic and World of Science, Vol. 53, page 232

Mason, Robert G. (1891) Ophthalmic, English Mechanic and World of Science, Vol. 53, page 233

Mason, Robert G. (1891) Cuticle of leaves, English Mechanic and World of Science, Vol. 53, page 278

Mason, Robert G. (1891) Microscopic – the splitting of selenite, English Mechanic and World of Science, Vol. 53, page 298

Mason, Robert G. (1891) Mirror, English Mechanic and World of Science, Vol. 53, page 343

Mason, Robert G. (1891) Case-hardening iron, English Mechanic and World of Science, Vol. 53, page 366

Mason, Robert G. (1891) Solder for gun-metal, English Mechanic and World of Science, Vol. 53, pages 389-390

Mason, Robert G. (1891) Microscopical, English Mechanic and World of Science, Vol. 53, page 436

Mason, Robert G. (1891) Mounting microscopic objects, English Mechanic and World of Science, Vol. 54, page 226

Mason, Robert G. (1891) Gun-metal castings, English Mechanic and World of Science, Vol. 54, page 271

Mason, Robert G. (1891) Plating solution, English Mechanic and World of Science, Vol. 54, page 291

Mason, Robert G. (1891) Microscopical, English Mechanic and World of Science, Vol. 54, page 293

Mason, Robert G. (1891) Do I Require Spectacles, 12 pages, printed by F. Shaw & Co. (reference from Google Books)

Mason, Robert G. (1896) Elementary photo-micrography, The Photographic News for Amateur Photographers, Vol. 40, page 124

Mason, Robert G. (1899) Practical hints on mounting, American Monthly Microscopical Journal, Vol. 20, pages 38-48

Museum of the History of Science (accessed 2013) Image and information on a Mason projection microscope,

Nature (1906) Advertisements by R.G. Mason, Vol. 74, pages xi and xxvii

Pharmaceutical Journal (1898) Exhibition of optical, mathematical, and scientific instruments, “R.G. Mason, of 69, Clapham Park Road, S.W., a trade maker, shows microscopes, etc.”, Vol. 61, page 402a

The Photographic Dealer (1898) Optical trades exhibition, “R.G. Mason, 69 Clapham Park Road, Clapham, S.W. In this case a strong exhibit of objects prepared for the microscope were on view”, Vol. 5, pages 81-82

The Photographic News for Amateur Photographers (1896) Report of meeting of the Brixton and Clapham Camera Club, Vol. 40, page 744

Probate record of Robert George Mason (1912) accessed through

Stevenson, Brian and Steve Gill (2013) The many lives of Heinrich Hensoldt (1856 – ca. 1918), Moritz Hensoldt’s errant son, Quekett Journal of Microscopy, In press

The Students’ Journal and Hospital Gazette (1883) Advertisement of slides for sale by R.G. Mason, Vol.11, page 221

Work (1893) Sale and Exchange advertisement from R.G. Mason, Vol. 6, page 174