Allan George Bromley (1947-2002) was an Australian historian of computing in the Computer Science Department at the University of Sydney. Internationally recognised as a leading authority on early computing devices—including the Antikythera Mechanism and Charles Babbage's Difference Engine—he was also one of the world's most dedicated collectors of calculating instruments. He displayed a small selection of his collection in the rear foyer of the Department of Computer Science (Fig. 1), while the vast majority was housed in his home, where his "assortment of analog computers [...] inspire[d] awe among fellow collectors and museum curators" (Sydney Morning Herald, 1999). His collection encompassed mathematical instruments, slide rules, mechanical and electronic calculators, electronic analogue computers, computer components, and related ephemera. Bromley began collecting calculators in 1977. Over the following two decades, his collection expanded to more than 3,000 objects and 10,000 books (pers. comm. Anne Bromley). It originated with approximately 500 slide rules, most acquired from London's antique markets during his time at the Science Museum. Over the years, it grew into the largest privately owned slide-rule collection in the Southern Hemisphere (Sydney Morning Herald, 1999). As both a collector and historian, Bromley reflected on the practice of collecting in his 1981 article Collectorabilia Dr. Allan Bromley, which may be the earliest published account devoted to the private collecting of computers and computer-related artefacts. Correspondence preserved in his personal papers provides further insight into the acquisition of rare analogue computers and other calculating devices. In the final years of his life, Bromley donated many of his most significant artefacts to the Australian Computer Museum Society and Sydney's Powerhouse Museum (now the Museum of Applied Arts & Sciences, MAAS), including a section of SILLIAC, Australia's second computer. He also played a pivotal role in the Powerhouse Museum's acquisition of a substantial portion of Charles Babbage's Difference Engine No. 1 in 1995. Acting on Bromley's advice, the museum purchased the piece at auction for $400,000; it remains one of only three surviving sections of the machine (Sydney Morning Herald, 2002). Following Bromley's death, other objects from his collection entered the private market. Today, his collection is a rare example of a calculator collection with a well-documented provenance. Each object bears a label marked "Bromley", together with the year of acquisition and its collection inventory number.

You're Collecting What! Collecting computers, by Allan G. Bromley
Sidney, Australia: Manuscript of 1981 publication

Description: Draft manuscript titled You're Collecting What! Collecting computers written by Allan G. Bromley, composed of 8 pages, accompanied with the published article COLLECTORABILIA Dr. Allan Bromley (pp. 58-60) in COMDEC magazine, October 81 issue. Selected excerpt: "Apart from the relative scarcity of memorabilia dating back more than a decade or so, there are certain practical difficulties involved in collecting computers from before about 1970 [...] A more practical proposition for those determined to start yet another memorabilia/collecting trend is to collect parts of computers - printed circuit boards, for example, or a vital integrated circuity or transistor type. Babbage would no doubt be impressed".

Together with additional ephemera documenting Bromley's collecting process:
(i) Handwritten aerogramme to Frank Percival, dated 8 January 1991. After discussing his work on the Antikythera Mechanism and commenting on the progress of the construction of the Difference Engine No. 2 at the Science Museum, Bromley reflects on his collecting activities in London: "Tramping around the markets of course. But there is very little to be had and even less at a modest price. I have bought a few small items. Mostly not really new, but improvements on existing items in my collection. As always same problems with books."
(ii) Correspondence concerning collecting 'holy grails': A 1991 letter from dealer Stuart Talbot offering the Thomas de Colmar calculator No. 899 for £2,800; together with 1994 faxes from Bromley's colleague Michael Wright reporting on Stanhope calculating machines (printed on thermal fax paper with Science Museum letterhead, one of which has almost completely faded).
(iii) Collection cards. Seven cards from January 1991 documenting Bromley's purchases in London. One records: "Two slide gager's slide rule | J. Long, 43 Eastcheap, LONDON | Light staining, otherwise good condition | £38". Also included are seven accession cards from 1977, documenting the earliest phase of Bromley's collecting (initially to examine calculator mechanisms rather than to build a collection), and a further eighty collection cards of a different format dating from 1979 to 1983 (some undated), none of which correspond to objects now in The Tricottet Collection.

Provenance: Allan G. Bromley

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Microscope and microscope-slide collections occupy a distinctive and highly specialised niche within the broader field of scientific collecting, at the intersection of scientific instrumentation and the preservation of medical, natural history, and geological specimens. Although the earliest microscopes emerged in the late 16th century, the Industrial Revolution accelerated both their manufacture and their popularisation, bringing the hidden wonders of the microscopic world to an expanding, fascinated audience. By the mid-19th century, enthusiasm for microscopy had become increasingly visible in public demonstrations, where leading instruments and remarkable microscopic preparations were exhibited to specialists and lay audiences alike. A famous illustration of such an event is reproduced in Figure 1 while a vivid contemporary account survives in the report of a microscopy session held in Antwerp during the 1885 Exposition Universelle. Describing the scene, the report notes: "On a large table, the instruments intended for the demonstrations were arranged in perfect order. Specimens were placed under the various microscopes, large and small, six in all, and everyone took turns examining the curious objects presented for observation." The preparations on display included cholera bacilli, J.D. Möller's Typen-Platten, H. Dalton's artistic butterfly-scale arrangements known as bouquets, and other remarkable specimens (Cornu, 1887).

Microscope Collections

The microscopes were often ornate instruments crafted in polished brass with intricate detailing, blending functionality with Victorian design aesthetics. As technological innovations multiplied, collectors could begin to envisage forming coherent collections and even attempting to complete sets. One of the earliest and most significant collectors was Sir Frank Crisp, who assembled almost 4,000 items, setting a precedent for later collectors.

Microscope Slide Holy Grails

"Arranged" slides, defined as "any preparation where the subjects have been placed in such a manner as to be displayed to best advantage" highlight the artistry of the mounter. Each slide could require many hours of meticulous work, and only a very small number were ever produced. As a result, arranged slides are among the most iconic and highly sought-after microscope slides for collectors. They emerged in the second half of the 19th century, enabled by improvements in microscopy, whereas until around 1850 most diatom slides were strewn mounts (Davidson, 2001). Around 1867, the talented preparer J.D. Möller began arranging them in orderly rows, one specimen per species. Thus was born the Type-slide, essentially a systematic collection contained on a single microscope slide. Beautiful in their own right as well as scientifically valuable, other forms of arranged slides were soon created according to purely aesthetic principles, featuring complex geometric patterns or pictures composed of hundreds of diatoms or butterfly scales. These became known as Exhibition slides or Salon slides since they were intended for display at soirées and the like (Bracegirdle, 1998b). Other names include Rosettes and artistic groups (Davidon, 2001). While J.D. Möller and Eduard Thum were preeminent in the production of exceptional Type- and Exhibition slides, Henry "Harold" Dalton's celebrated butterfly-scale pictures place him alongside them among the finest mounters of the 19th century. Today, the most elaborate Type- and Exhibition slides rank among the Holy Grails of microscope-slide collecting, with collectors often seeking examples containing the greatest number of mounted specimens.

Scholars in the History of Microscope Collecting

If the heyday of microscope collecting belonged to the Victorian era, today's fascination for historic microscope and slides is reflected in the scholarly works of Brian Bracegirdle (1933-2015), the first Keeper of the Wellcome Museum, and Brian Davidson (?-?), an exceptional collector of antique microscope slides. Bracegirdle authored the standard reference work Microscopical Mounts and Mounters (Fig. 2), while Davidson published two seminal articles on arranged slides (Davidson, 2001; 2008). Together, they produced a substantial body of scholarship on the history of microscope slide mounting. Some slides from Davidson's collection, including examples illustrated in his own publications and in Bracegirdle (1998), remain preserved today. Unfortunately, Davidson's remarkable collection was dispersed anonymously through a series of auctions and was never fully documented. Rare slides and collection catalogues in the TC with confirmed or presumed Bracegirdle or Davidson provenance are identified accordingly.

Fig. 2. Exhibition slide titled Christmas tree novelty slide, made of "dried stems of colonial hydroids as the tree and its branches, with tiny shells as baubles". Featured on p. 211, no. F, plate 53, Some "Exhibition" slides in Bracegirdle (1998). Provenance not confirmed, but very likely from Davidson, or possibly from Bracegirdle himself, who wrote that he had "been given the unstinting support of Brian Davidson, and encouraged by him to borrow what [the author] would from his comprehensive collection of preparations, for investigation and for inclusion in the plates" (Bracegirdle, 1998a: preface). Other Christmas slides from Davidson shown here.

Fig. 3. An exhibition slide from the Davidson collection featured in Davidson (2001) - COMING LATER.

Arranged Diatom Slides, by J.D. Möller
Wedel in Holstein, Germany: 1868+

Description: Arranged diatom slides by J.D. Möller, cherry-picked for the TC:
(i) Numbered Möller-400 Type-slide, consisting of four groups of c. 100 diatoms in square arrangements, described as "epic" by its former owner, Howard Lynk of Victorian Microscope Slides. Slide engraved "Diatomaceen=Typen=Platte | Deckglasdicke 1/6 Mm | No 32" and "I.D. Möller | Wedel in Holstein | Germania | 1868." In leather case with gold wording to the lid which reads "J.D. MÖLLER'S DIATOMACEEN-TYPEN-PLATTE", with blue velvet lining and cream silk to the lid - The 32nd Type-slide by Möller, of at least 195 known to have been numbered by 1870.
(ii) Numbered Möller-400 Type-slide key, leather-bound booklet titled in gilt "VERZEICHNISS ZUR TYPEN-PLATTE", with handwritten introduction in English with illustration of the diatom slide No. 21, 16 pp. of text in English describing 384 specimens, signed and dated at the rear "Wedel in Holstein, Octbr. 1868, J.D. Möller, Préparateur" - This example proves that young Möller was astute enough to understand the potential of the British market, also that he obtained at least some his diatoms locally. As indicated by Davidson (2001), "often the key shet or booklet has not been kept with the slide, and unless the owner is the person who disposes of it, the slide may be unintentionally separated from its list, especially when a century or more has passed since the slide was mounted," a case in point here with slide no. 32 and catalogue no. 22 in the TC.
(iii) Early Möller-100 Type-slide, a rare example that is engraved "II. Diatomaceen=Typen=Pl. | Deckglasdicke 1/9 Mm" and "I.D. Möller | Wedel in Holstein | Germania | 1871." with matching printed key (folded, dated October 1871). In classic Möller leather case.
(iv) Exhibition slide, with round green label "J.D. MÖLLER".

Provenance: (i) Howard Lynk. (ii) Brian Davidson

References: (ii) Davidson, B. (2015), The Genius of J. D. Möller Préparateur. Christmas Quekett Lecture, 55 min. - J.D. Möller signature of present copy used as presentation title, "I had the good great fortune many years ago to be offered" this copy (19’30”-22’00”).

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Arranged Diatom Slides, by Eduard Thum
Leipzig, Germany: 1875-1900s

Description: Arranged diatom slides by Eduard Thum, cherry-picked for the TC:
(i) Type-slide with 382 (!) items, a rarity for Thum's Type-slides, arranged in perfect alignment. Slide bearing two Thum labels titled "Rus Marin. Typen-Platte d. Diatomeen a. Frepang v. China" and "Mikrosk. Institut. 390 Formen i. Monobrom Naphtalin. E. Thum. Leipzig". Large bubble present not affecting the mount - To date, we have not identified another Thum type slide containing more than c. 400 specimens. Stevenson (2018) notes that, by 1891, Thum had produced a slide containing 1,230 diatoms arranged in the form of a monogram, which was presented by the San Francisco College of Pharmacy to A. H. Breckenfield in recognition of his valuable course of lectures on microscopy. This demonstrates that Thum's finest arranged slides were conceived as true trophies.
(ii) Exhibition slide, bearing two Baker labels titled "C. BAKER. Salon-Slide Pleurosigma-Rosette. 244.H.HOLBORN" and "LONDON.W.C.. 67 forms No. 4749. E. THUM, preparer, Leipzig".

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Picture slide of butterfly scales, by H. Dalton
France: 1880s+

Description: Butterfly scale exhibition slide, with distinctive bright green labels "HAROLD DALTON Preparer LONDON & PARIS" (minor loss to sticker) and "Butterfly Scales arranged as a Basket of Flowers with Butterflies" - Typical of Dalton's exquisite work, the basket is like a miniature still-life painting, with a life-like and vibrant three-dimensional quality (to use the words of Davidson, 2008). His artistry is illustrated for example by the use of colours.

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Sir Frank Crisp, Baronet (1843-1919), was an English lawyer, horticulturist, microscopist, and officer of the Royal Microscopical Society (RMS), who built an unrivalled, vast, and spectacular collection of microscopes in the 1870s and 1880s. He joined the RMS in 1870 and was elected to the Council in 1874, becoming one of its Secretaries in 1878. He later became Treasurer and was elected Vice-President four times between 1893 and 1897 (Insley, 1982; 1984). Recognised as the leading authority on the history of the microscope, he was able to obtain many rare and interesting forms, a feat never to be repeated. By 1890, Crisp was sufficiently well known as a collector of microscopes to be the subject of a cartoon in Vanity Fair (Fig. 1). His collection, consisting of nearly 3,000 microscopes and over 1,000 pieces of apparatus, was sold by Stevens's Auction Rooms after his death in at least five sales between 1920 and 1925, attesting to its sheer size (Stevens's Auction Rooms, 1925; see III.2.i). The lack of a proper catalogue of his collection and a history of its rarest holdings before its dispersal has been considered "an international calamity" (Gunther, 1925). This, however, prompted historians of collecting to investigate the surviving evidence of the contents of the Crisp collection. Impey (1984) wrote: "The material evidence of the contents of the Crisp collection is complicated, and scattered. No single complete listing exists. Crisp had engravings made of many of his instruments [...] He also wrote description sheets..." giving the type of microscope, maker's name, shelf number, and occasionally the date and place of purchase. These sheets were also dispersed at the sales, some accompanying the corresponding microscopes, with several eventually reaching the Science Museum, London. Collector Thomas H. Court (1868-1951; Insley, 1982), who had inspected the Crisp collection before its sale, also produced a drawing of the collection room layout, which is likewise preserved at the Science Museum. The engravings depicting the Crisp collection have been bound in various ways. Impey (1984) lists the few known copies: two copies purchased at the last Crisp sale by Robert Gunther (1869-1940, founder of the Museum of the History of Science, Oxford), another acquired by Gunther through a newspaper advertisement; three volumes held by the Museum of the History of Science at Oxford (marked "Vols. I and II", "IIIA", and "IIIB" - the Gunther copies?); and one volume bound by the RMS (now the TC copy; see III.2.i). These engravings, especially the annotated ones, and the manuscript sheets are "invaluable" for verifying a Crisp provenance, since the instruments themselves were never marked by Crisp. Microscopes known to have once belonged to the Crisp collection can now be found at the Museum of the History of Science in Oxford, the Wellcome Museum of the History of Medicine at the Science Museum, and the Science Museum's Department of Physics (Impey, 1984). The final sale of the Crisp collection, which took place in 1925 at Stevens's Auction Rooms, was reserved for "the earlier and rarer Microscopes" and was described as "the first occasion on which a Collection of Antique Microscopes has ever been catalogued for sale by Public Auction" (Stevens's Auction Rooms, 1925).

The Album MICROSCOPES IN MR FRANK CRISP'S COLLECTION
England: Sir Frank Crisp, sheets for private circulation, turn of 20th century

Description: A unique set of engravings depicting objects from the Crisp microscope collection, possibly bound by the RMS (Impey, 1984: 20). Folio album, half-leather binding, with green faux-leather boards and a black leather spine lettered in gilt: "MICROSCOPES IN MR FRANK CRISP'S COLLECTION". Minor loss to the spine decoration at the foot; orange endpapers, with a pocket of matching material to hold a copy of the 1925 auction catalogue (see below). Previous owner's signature crudely erased from the upper corner of the inside page. "Royal Microscopical Society" stamped on p. 31. "B. BRACEGIRDLE" written in black ink below the pocket; front leaf repaired with tape, with "B.B." noted underneath. The album comprises 78 pages of engravings depicting the principal microscopes in the Crisp collection, as well as the collection's shelving units and display cabinets, illustrated at the rear of the volume. Many engravings bear handwritten annotations, mostly in pencil, with some in ink, suggesting the possibility of two different annotators (though none in Crisp's hand). It is one of only four-to-seven known Crisp albums, although the contents of these copies differ (Impey, 1984). The TC has yet to study this copy and compare it with the others known to exist.
Accompanied by A Catalogue of the Collection of Antique Microscopes, formed by the late Sir Frank Crisp. Stevens's Auctions Rooms, Tuesday, February 17th, 1925, 31 pp. In the original peach-coloured, titled wrappers, fully priced in black ink, with a few pencil notes (as in the album). "B. BRACEGIRDLE" on the cover and "B.B." on the title page.

Provenance: The Royal Microscopical Society • Brian Bracegirdle

References: Disney et al. (1928:285); RMS (1929:30); Insley (1984:20) - Listed in the 1928 RMS catalogue as "CRISP, FRANK, Sir, F.R.M.S. | Plates of his collection of Microscopes. | [Unfortunately unindexed and undescribed]" (see III.2.ii below). Described in Insley (1984): "A collection of engravings of microscopes from the Crisp collection was gathered together and bound by the Royal Microscopical Society, and appears in their library catalogue of 1929. This volume was sold when a rationalisation of the library took place, and is now in private hands, together with a catalogue from the 1925 sale annotated in an unknown hand. Some of the engravings appeared in the Journal of the Royal Microscopical Society during the time Crisp was Editor."

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Instruments... in the Collections of the Royal Microscopical Society
London: The Royal Microscopical Society, 1928

Description: DISNEY, Alfred N., HILL, Cyrill F., BAKER, Wilfred E. Watson, eds. (1928), Origin and Development of The Microscope, as illustrated by Catalogues of the Instruments and Accessories, in the Collections of the Royal Microscopical Society, together with Bibliographies of Original Authorities. London: The Royal Microscopical Society, xi, 303 pp., 30 plates, 36 text-figures - The first part provides a detailed history of the microscope. The second part is the catalogue of the RMS collection, with the donor and date of acquisition provided when known. A later RMS catalogue is Gerard L'E. Turner's 1989 The Great Age of the Microscope: The Collection of the Royal Microscopical Society Through 150 Years. The 1928 edition is of particular interest to the TC for its listing of the RMS copy of the very rare Crisp album (see III.2.i). Two copies in coll.:
(a) Presented by C.F. Hill: Unique blind-stamped blue-board binding, possibly made for presentation. Sunning to the spine and front board. Inscribed on the front flyleaf: "With all good wishes from C.F. Hill, a memento of many happy hours work together. May 1928".
(b) Presented by W.E.W. Baker: Standard blue-board binding, with sunning to the spine and front board, a horizontal scratch across the front board, and the spine covering partly detached. Inscribed on the front flyleaf: "With Kindest regards from Wilfred E. Watson Baker | Aug 1928".

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Injection/corrosion Anatomical Specimens
Vienna: Prepared by J. Hyrtl, 1860s

Description: Cased set of Hyrtl injection/corrosion specimens for the microscope, 1860s. Twenty-four slides with printed labels to the reverse. Contained in a French polished mahogany slip case with a leather label to the lid bearing gold lettering: System Lymphaticum, nervosum, fibrosum et cellulare. Each slide consists of a 45 × 30 mm ebony frame containing a central cavity in which the injected specimen is mounted in balsam beneath a glass cover (see Figures 1-3 in Hyrtl, 1873). In the appendix to his collection catalogue (Hyrtl, 1864), Hyrtl notes that his series of microscopic injection preparations included multiple duplicates of each number, intended for exchange or sale. In his 1873 catalogue, he further explains that "the preparations and the cover glass form a single unit and are therefore completely protected from all harmful external influences. The cover glasses are framed in ebony holders, with an explanatory label affixed to the back of each frame. In this mounting, the preparations are truly indestructible, withstand the roughest handling, and can even endure being stepped on without damage [...] I have preserved some of them for a period of 35 years; they are today as beautiful and intact as on the day they were made". Cases were produced in formats of 12, 24, 48, 96, or 120 preparations. In 1873, a set of 24 was priced at 20 Thalers. Hyrtl also indicates that sets could be exchanged for comparative anatomical material, including human and animal skulls (particularly exotic species), freshwater fish and reptiles from India and South America, and other natural history curiosities. These injection preparations are now considered rare survivals and are seldom encountered in private collections. It remains unclear how many sets have survived; the present example corresponds to one of only a few (4) recorded on the market in recent decades (Flints, 2020, lot 23). In the 1873 sale catalogue, Hyrtl notes that, together with remaining material from earlier catalogues, his stock comprised approximately 500 items, each with 4 to 20 duplicates, "a truly respectable stock for the new business exchanges now being initiated". It is likely that "items" refers to individual specimens rather than complete sets.

Provenance: Josef Hyrtl

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Catalog der, in der Privatsammlung..., by Josef Hyrtl
Vienna: Wilhelm Braumüller, 1865

Description: HYRTL, Josef (1865), Das Vergleichend-Anatomische Museum an der Wiener Medicinischen Facultät in Jubliläumsjahre 1865. Nebst einem Anhang: Catalog der, in der Privatsammlung des Herausgebers Befindlichen Skelete, Gehörorgane, und Mikroskopischen Injections-Präparate. Vienna: Wilhelm Braumüller, 213 pp. 213 pp. (museum catalogue) + 41 pp. (catalogue of Hyrtl's private collection). Original yellow wrappers- Published to commemorate the jubilee year of the Vienna Medical Faculty, this important catalogue documents the holdings of the Comparative Anatomical Museum, listing specimens of mammals, birds, amphibians, and fishes. The work represents the culmination of 14 years of effort and underscores Josef Hyrtl's central role in establishing the museum, which he regarded as an essential foundation for the creation of a dedicated chair of comparative anatomy. The catalogue reveals that the museum's collections were built through purchases, exchanges, and donations. The museum itself is described as comprising elegant display cabinets devoted primarily to articulated skeletons, carefully prepared and mounted in lifelike poses, alongside smaller cases housing diminutive specimens and anatomical preparations preserved in spirit. An especially significant feature is the appendix, Catalog von Fisch- und Amphibien-Skeleten, sowie von Gehör-Organen und mikroskopischen Injections-Präparaten, welche sich im Privatbesitz des Herausgebers befinden, which inventories the skeletons, auditory organs, and microscopic injection specimens in Hyrtl's own collection. Hyrtl regarded his private holdings as complementary to those of the university museum. Most of the specimens were prepared by Hyrtl himself, while others were acquired at his own expense or obtained through exchanges of his renowned injection and corrosion preparations.

Catalog Mikroskopischer Injections-Präparate, by Josef Hyrtl
Vienna: Wilhelm Braumüller, 1873

Description: HYRTL, Josef (1873), Catalog Mikroskopischer Injections-Präparate. Vienna: Wilhelm Braumüller, 40 pp., 3 figs. In original yellow wrappers, uncut - In this sale catalogue, Hyrtl showcases the exceptional quality of his anatomical injection preparations, emphasizing the superiority of his injection technique and the scientific value of the specimens offered.

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Perlen aus der Instrumenten-Sammlung von Paul de Wit
Leipzig: Paul de Wit, privately published, 1892

Description: DE WIT, Paul (1892), Perlen aus der Instrumenten-Sammlung von Paul de Wit, Leipzig. Leipzig: Verlag Paul de Wit. 14 pp., 16 chromolithographic plates by Emil Pinkau, descriptive text in German, French, and English. Oblong folio, original board wrappers preserved in a specially made binding, upper cover with central sunken panel featuring a colour illustration of four musicians, with elaborate metalwork in each corner:
(i) Presentation copy in velvet binding, inscribed: "Hommage de reconnaissance et de sincère admiration de la part de l'auteur! Leipzig, 3 Octobre 1903, Paul de Wit".
(ii) Presentation copy in grey (or discoloured) binding, title page taped, inscribed: "Souvenir de l'éditeur à M. le dr. Maurice Emmanuel de Paris, Paul de Wit, Leipsic, le 26 Octobre 1897" - Maurice Emmanuel (1862-1938) was a French composer and musicologist and one of the genuine independents in French music.
The album was likely issued in connection with the 1892 theatre and music exhibition in Vienna.

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