Arthur Cottam, 1836 - 1911

by Brian Stevenson
last updated February, 2015

Although he was a clerk by trade, Arthur Cottam enthusiastically explored many fields of science. He was an early member of the Royal Astronomical Society and the Quekett Microscopical Society, and was a founder of the British Astronomical Association and the Watford Natural History Society. His interests were almost entirely hobbies, an exception being an 1889 venture into selling his star charts.

Cottam is best known among slide collectors for his good quality preparations of diatoms (Figure 1). Far less common are his slides of other subjects, which include plants, fungi and insects (Figure 2).

Figure 1. Microscope slides of diatoms by Arthur Cottam. Each preparation contains a few selected representatives of one species – a photomicrograph of his Biddulphia pulchella is shown as an example.

Figure 2. Cottam prepared slides of many different types of specimens, reflecting his broad interests that included entomology and botany. Some images are from internet auction sites, and are used here for nonprofit, educational purposes.

Figure 3. Arthur Cottam’s distinctive monogram. Possibly because of the broad serif on top of the monogram’s letter “A”, some publications mistakenly give Cottam the middle initial “T”. All identified legal records indicate that Cottam did not have a middle name.

Arthur Cottam was born April 9, 1836, in Camberwell, Surrey, England. His father, Thomas, was a relatively well-to-do merchant. Arthur’s mother, Sophia Emma Barraud Cottam, was a niece of Elizabeth Barraud Cole, who was the mother of well-regarded professional microscope slide-maker Arthur Cole. In one of Cottam’s published papers, he thanked Cole for lending a slide of a rare diatom, indicating a relatively close relationship between the cousins.

At the time of the 1841 census, Thomas, Sophia, Arthur and his three little sisters lived at Thomas’ brother’s house in Blackheath, Lewisham, Kent. Thomas died in 1849, when only 43 years old. Sophia and her children (by then, 8 in number) remained with the brother, James, and his family. James was recorded in censuses as being a “colonial broker” and “underwriter at Lloyds”.

Arthur began work in 1851, at the age of 15, as a junior clerk with government’s Office of Woods and Forests. His initial salary was £90 per year. He remained with that agency for the rest of his working life.

He married Mary Gibbs, by banns, on July 8, 1860, at Little Stanmore, Middlesex. Church records indicate that Arthur was a member of that parish. The 1861 census recorded that Sophia and her family, and James and his family, had by then moved to Little Stanmore, suggesting that Arthur had continued to live with the family until his marriage.

Shortly after marrying, Arthur and Mary moved to Putney, Surrey. Arthur presumably benefitted from his father’s estate, since the 1861 census recorded that the 24 year-old “assistant clerk” and his wife had a live-in house servant. Their first of three children was born that year. The second was born during early 1863, in Putney, while the third child was born during late 1864 in Watford, Hertfordshire. Arthur and Mary remained in Watford until after the turn of the 20th century.

Cottam was elected to membership in the Royal Astronomical Society on February 14, 1862. Letters and his RAS obituary indicate that he owned a Merz 4 ½ inch refracting telescope and a custom 12 inch reflecting telescope that he acquired from Nathaniel E. Green. Cottam wrote that “My Observatory here stands at an elevation of 500 feet above the sea level, and it is very rarely that I am prevented by fog from making observations”.

He joined the Quekett Microscopical Club on May 28, 1869. Arthur served on the Club Committee from 1876 through 1878. Minutes of the QMC’s August 25, 1876, ordinary meeting report that a “photograph of Mr. A. Cottam” was donated to the Club “for the album”. That album contained dozens of photographs of QMC members – one wonders if it is still in existence and if the QMC would permit exhibition of those pictures.

Both the RAS and the QMC listed Arthur Cottam’s address as Whitehall Place, S.W., which was the London address of his employer. Either Cottam daily commuted 20-odd miles each way to work in the city, or worked at a branch near Watford but received mail at the Office of the Woods’ main office.

In 1875, Hardwicke’s Science-Gossip reported, “Natural History, &c., Society At Watford - It is always with great pleasure we record the foundation of any fresh centre for the united study of Natural History, and therefore we are glad to learn that it is intended to form a society, having for its object the investigation of the Meteorology, Geology, Botany, and Zoology (including Entomology, Ornithology, &c.) of the neighbourhood of Watford, and the dissemination amongst its members of information on Natural History and Microscopical science. The evening meetings of the society are to be held in the rooms of the Watford Public Library, and during the summer months field meetings will also be held. It is proposed that the annual subscription be ten shillings, without entrance-fee. The names of ladies and gentlemen willing to join the society will be received by Dr. Brett, Watford House; by Mr. Arthur Cottam, St. John's-road, Watford; and by Mr. John Hopkinson, jun., Holly Bank, Watford. It was hoped that a sufficient number of names will be shortly received to warrant a meeting being called to found the society at once”. Arthur Cottam served as its first Treasurer, and as a member of the Council.

The Watford Natural History Society, together with the Hertfordshire Field Club, began publishing their Transactions in 1875. An early issue included Cottam’s April, 1875 “Notes on the flora of Watford District”, an extensive list which he said “contains some of the plants which in two years’ not very careful or continuous collecting I have come across in this District. Many others more common are, of course, omitted. I have added in parentheses a few that I believe are, or at least ought, to be found here, but which have escaped my notice”. Later that year, Science-Gossip reported later in 1875 that “At the October meeting of the Watford Natural History Society, Mr. Arthur Cottam read a ‘Note on the Appearance of Sphinx convolvuli’, in which he mentioned that several specimens of this moth had recently been taken in the neighbourhood of Watford. Two were taken by a postman, who, when delivering the letters in the morning, found them on door-knockers”.

At the Society’s March 9, 1876 Ordinary Meeting, “Mr. Arthur Cottam, F.R.A.S., delivered a lecture ‘On some of the Simpler Methods of Microscopical Mounting’, which he illustrated practically by mounting objects dry and in Canada balsam. In treating of the cements employed in dry mounting, he stated that gum-water should be made with perfectly cold water, with a small quantity of alcohol and a little glycerine added; that a mixture of india-rubber, asphalte, and mineral naphtha formed the best cement; and that Canada balsam was not to be relied on at all, becoming brittle. As an illustration of mounting in Canada balsam, he mounted some diatoms, taking a glass slide, subjecting the diatoms to a dull red heat, placing them in a medium consisting of two parts of balsam to one of benzole, slightly heated, and dropping on the thin glass cover, having previously warmed the slide to prevent its cooling the balsam suddenly, and so producing air-bubbles. He stated that the chief difficulties in these simple methods of mounting were to get rid of moisture and air-bubbles; it was more necessary to get rid of moisture when mounting in balsam than dry, and more difficult to get rid of air-bubbles in glycerine jelly - a favourite and very useful medium - than in balsam. He recommended Mr. Davies' work, in the Society's library, as the best guide to microscopical mounting”.

At that same meeting, “It was announced that field meetings had been arranged, in conjunction with the Quekett Microscopical Club, for June 3 at Bricket Wood, and for July 1 at Elstree Reservoir and Stanmore Heath”. That was likely coordinated by Cottam, being a member of both societies.

Cottam published a major paper on a diatom in the Journal of the Quekett Microscopical Club in 1876, having lectured on the topic in February of that year. His report included a plate of drawings made by Cottam (Figure 4). Some excerpts:

“On A New Aulacodiscus, From The West Coast Of Africa. By Arthur Cottam, F.R.A.S.

It appears to me that the West African diatom differs in some respects so distinctly from both the species with which it has been connected, that it may be considered a new species, and I propose to call it Aulacodiscus Africanus, by which name Mr. Martin, I believe, wishes it to be known. I should describe it as follows: Aulacodiscus Africanus. Disc hyaline, with 8, 4, or 5 submarginal processes, each covered with a highly developed circular hood. Valve inflated under each process, in the centre usually a small umbilicus surrounded by a rosette of oblong cellules. Granulation minute, crowded, radiant, and equal in size all over the valve. Diameter from .0046" to .0021". Recent, Banana Creek, on the West Coast of Africa”.

Cottam’s A. africanus is still an accepted species name, without synonym.

Figure 4. Drawings by Arthur Cottam that accompanied his 1876 paper on a new species of diatom. From his original legend: “ 1 Aulacodiscus Africanus, side view, a large specimen. 2 Ditto ditto a small specimen. 3 Ditto on its edge. 8 Ditto front view. 4 Aulacodiscus Kittoni (recent) New Zealand. 5 Ditto on its edge. 6 Ditto (Fossil) Mexillones deposit, Bolivia. 7 Aulacodiscus Johnsonii. Algoa Bay Guano, (a) Process broken off. All the figures are drawn to a scale of 400 diameters”.

Relating to Cottam’s artistic skills, in 1887 he presented to the QMC, “On the ‘autographic’ process of lithography as applicable to the illustration of scientific papers”. His publication on this improved method of producing lithographic plates began, “It will, I doubt not, be readily admitted that the value of many a scientific paper is greatly increased by good illustrative plates. Many papers would be almost unintelligible unless illustrated. And again the value of the illustrations is very much greater when they are drawn by the author of the paper they are intended to illustrate. To have plates drawn by a professional draughtsman is always expensive work, and unless the draughtsman has some knowledge of the objects to be figured, it is a matter of no little difficulty - sometimes almost an impossibility - to explain to him the special features that are to be brought out, and the minute differences and gradations of light and shade upon which the value of a drawing frequently depends. A process that will enable any one who can draw fairly well - and I suppose all microscopists can draw more or less, at all events they should be able to do so - to draw his own figures, and to have them printed in facsimile in any numbers, and at a very small cost, is a process so likely to be valuable to the members of this Club, that I am anxious to introduce the new ‘Autographic’ process to you, as I believe it will be found to possess all these advantages”.

Meanwhile, in Watford, Cottam seems to have been almost alone in having an interest in microscopy. The Council Report for 1877 lamented upon the state of the club, “It may be here pointed out that, if we exclude the short notes from our consideration, in 1875 - the first year of the Society's existence - geology and botany were almost the only subjects upon which papers were read; in 1876, geology and meteorology, there not being a single botanical or zoological paper; and in 1877, meteorology, botany, and zoology, no geological paper having been communicated. Taking therefore the three years together, each of the sciences for the advancement and study of which the Society was founded has received a fair amount of attention. Little has however been done with the microscope - Mr. Chater's paper on "Microscopic Fungi," and a lecture by Mr. Cottam on "Microscopical Mounting," being the only communications during the three years on any subject for the elucidation of which the microscope is necessary. An attempt was made in the spring to hold a series of extra informal meetings for the examination of microscopic objects, but so few microscopes were brought, and the attendance of members was so small, that the experiment can ‘be said to have been successful’. The microscopic object cabinet, also, purchased in 1876, does not yet contain a single object. Several have been promised, and if a small collection of slides could be got together it would doubtless encourage members to add to this nucleus any duplicates they may have, and some perhaps to mount objects, or to purchase them, specially for the Society”.

Perhaps an effort to stimulate Watford’s interest in microscopy, Cottam enthusiastically talked in 1879 on John Matthews’ “Micro-megascope”, “I am anxious to introduce to the members of this Society a contrivance, which was recently shown by Dr. Matthews at a meeting of the Quekett Microscopical Club, for converting an ordinary microscope into what Dr. Matthews calls a ‘Micro-megascope’, for the reason that it is possible to magnify or diminish the object under examination at will by decreasing or diminishing its distance. Some similar arrangement had been used before, but Dr. Matthews worked it out independently and made one great improvement, an all-important improvement, on what had previously been done. The arrangement consists in placing a low power objective - I find a 3-inch is best - in an adapter in the sub-stage. It must be placed with its front combination upwards, that is, towards the body of the microscope. It is this reversed position of the lower objectglass that is the great point of Dr. Matthews' discovery. Another object-glass - 2-inch or 1-inch, or a higher power - is placed in the ordinary way on the nose of the microscope body. It is necessary to remove the mirror, and to place the object on the table below the lower objective. The lower objective forms an aerial image, which is then magnified by the upper object-glass. This arrangement really converts the microscope into a low power terrestrial telescope, for the object may be placed any distance away, but the nearer it is brought to the lower objectglass, the more it is magnified. The arrangement has great advantages - the object is seen erect instead of being inverted as usual in the microscope - the definition is perfect, and the field wonderfully flat, so that it is easy to draw very convex objects with the camera lucida. Dr. Matthews' paper upon the subject in the 'Journal of the Quekett Microscopical Club’, vol. v, p. 167, explains other methods of working with it, and is well worthy of study”.

At the June 12, 1879 meeting of the Watford Natural History Society, “The President said that the Hydrographer at the Admiralty, who had just returned from Cyprus, had given him a bag of mud which had been brought up by an anchor from a depth of 4 1/2 fathoms in the harbour of Famagusta, which he had been surveying. Mr. Cottam being interested in the Diatomaceae, he would hand the bag to him for examination, only asking him to give them notes on any discoveries he might make”. I have not found any reports or slides made by Cottam on this matter.

Early in 1889, Arthur published a set of “charts of the constellations”. A second edition of the large scale maps was printed in 1891, as was also a less-expensive “popular edition” of lower-scale charts (Figure 5). The original version was described in Nature, “Mr. Arthur Cottam has projected a series of thirty-six most excellent charts of the constellations from the North Pole to between 35° and 40° of south declination, and showing stars in half magnitudes down to 6 1/2 by disks of various sizes. Although the primary object in constructing these charts was to make them companions to Webb's ‘Celestial Objects for Common Telescopes’ and Smyth's ‘Cycle of Celestial Objects’, their scope has been considerably enlarged, and a number of double, multiple, and variable stars have been laid down which are not included in either of the above-mentioned works. The Earl of Crawford's (Dun Echt) summary of F.G.W. Struve's Dorpat Catalogue included 2248 double and multiple stars, and of them, 2130 are shown upon these charts. In addition to this, 275 of the double stars discovered by Mr. S.W. Burnham have been mapped, this being the whole of those included in his first four catalogues, and a selection from his other catalogues. The maps have been drawn to a scale of one-third of an inch to a degree, which is a much larger scale than any hitherto published, and as each map includes but a small portion of the heavens, there is practically no distortion, whilst the epoch being 1890, the positions will hold good, without any serious errors, for fifteen or twenty years beyond that date. The projection is conical, or, in those charts which extend any distance both north and south of the equator, cylindrical. Hence it will be easy to lay down any additional objects that may be required. There is no doubt that these charts will be eminently useful, one of their great advantages being that they will enable possessors of telescopes mounted on altazimuth stands or without circles to find with ease a large number of interesting objects, and thus will help to extend the knowledge of the heavenly bodies and to popularize the most fascinating of sciences. We may say that the publisher of these charts is Edward Stanford, Cockspur Street, S.W., and that the first issue is limited to 200 sets, many of which have been already subscribed for”.

Cottam was elected to be director of the “Jupiter” section of the British Astronomical Association in 1899. This meant that he was responsible for coordinating studies and descriptions of observations on the planet Jupiter.

Figure 5. 1891 advertisements for Arthur Cottam’s star charts.

Cottam also had a strong interest in entomology, especially studies of lepidoptera (moths and butterflies). Examples of his enthusiasm include this 1878 report to the Watford Natural History Society, “Mr. Arthur Cottam gave some particulars of his own experience in collecting. With regard to the female orange-tip (Anthocaris Cardamines) being mistaken for the Bath white (Pierii Daplidice), he remembered an instance of the reverse - Daplidice mistaken for the female Cardamines. He had had the pleasure of taking a male Daplidice at Margate in 1868, and a few minutes later he took Argynnii Lathonia and about twenty specimens of Coliat Byale. Although this was usually rare, it was sometimes as abundant as C. Eduta. In 1868 he saw a good many on the South Coast, although none had been seen there for some years before. He believed that Hipparchia Semele was chiefly found in the Chalk districts. It settled with its wings closed, and in this state it could scarcely be distinguished from the chalk. Several specimens of the Camberwell beauty (Vanessa Antiopa) were seen in the neighbourhood of Hoddesdun in 1875, and it had certainly been also seen in Middlesex”, and this 1899 letter to The Entomologist, “Stauropus Fagi At Watford And Ealing - On July 6th a fine fresh male specimen of this species flew into my dressing-room, attracted by the incandescent gas-light. The following night another came to the window, which happened to be shut, and before I could open it the insect flew off; but I had a good view of it before it went. I am not aware that this moth has been taken in this district previously. My friend Mr. Laurence Miles, of Ealing, had one brought to him by a policeman, who took it off one of the electric (arc) lamps there. Not knowing that the insect was a rare one, he took no note of the date”. Collectors of historical microscopy will recognize that Laurence Miles was also a hobbyist microscope slide-maker, whose diatom preparations are strikingly similar to Cottam’s, even bearing comparable monograms.

Cottam evidently amassed a considerable collection of butterflies and moths, which was auctioned in November, 1911, just a few days before Cottam’s death from a prolonged illness (Figure 6).

Figure 6. A 1911 advertisement for the auction of Arthur Cottam’s butterfly collection. Until just a few years before this auction, the J.C. Stevens Auction Rooms had been operated by Samuel Stevens, who also retailed microscope slides and other scientific items.

Arthur retired from the Office of Woods in 1905, whereupon he and Mary moved to Somersetshire. They settled at “Furzebank”, Durleigh Road, Bridgwater. The Hertfordshire (formerly Watford) Natural History Society wrote in The Entomologist, “By the removal of Mr. Arthur Cottam from Watford … the Society lost one of their most careful observers. Before leaving the county he sent a short note recording the capture on June 3rd, at Aldbury, of a specimen of Chaerocampa porcelius, a species which he subsequently took in his garden at Watford, flying over honeysuckle”.

Cottam’s middle child, Frances Mary, had died in late 1877, when only 15 years old. In March of 1911, his eldest, Arthur Basil, died as a consequence of an operation.

By March, 1911, Arthur was seriously ill. Mary filled out and signed that year’s census forms, stating that the household included a professional nurse. Arthur Cottam passed away at home, on November 23, 1911. His death was noted in not only entomological and microscopy journals, but also in one of the world’s pre-eminent scientific journals, Nature.

Nature: “We regret to see announced the death, on November 23, of Mr. Arthur Cottam, at seventy-five years of age. Employed as an official in a Government department during a great part of his life, he was an enthusiastic amateur astronomer. He was elected a fellow of the Royal Astronomical Society so far back as 1862, and was one of the original members of the British Astronomical Association, being its secretary from its foundation in 1890 to 1892, when he resigned owing to increasing pressure of official duties. In 1898 he became director of the Jupiter section of the association, an office which he retained until 1903. Mr. Cottam is best known by an excellent star atlas, ‘Charts of the Constellations’, which he published in 1889. These charts show all stars down to about the 6.5 magnitude, from the North Pole to between 35° and 40° of south declination, for the epoch 1890. Originally projected as companions to Webb's ‘Celestial Objects’ and Smyth's ‘Bedford Catalogue’, their scope was considerably enlarged, and they show many original features. Each map usually gives one constellation only with the region around it, and the brighter stars have much larger discs than usually given, so that the leading stars in the maps are those which catch the eye by their brightness in the heavens”.

Monthly Notices of the Royal Astronomical Society: “Arthur Cottam was born at Camberwell on 1836 April 9. At the age of fifteen, his father having died the year before, he entered the office of Woods and Forests, where he remained till he retired when nearly sixty years of age. The routine of a Government office was not what he would have chosen, and every leisure moment was devoted by him to scientific and artistic pursuits; he thus accomplished a large amount of interesting and valuable work. Mr. Cottam’s talents were many and varied. He was an accomplished artist and musician; and his scientific interest included astronomy, microscopy, entomology, and botany. It was one of his characteristics to spare no pains in bringing his work to the highest state of perfection of which it was capable, and the delicacy of his manipulation is evidenced by the exquisite mounting and arrangement of his various collections. In microscopical slide mounting he had few rivals…Mr. Cottam used two telescopes in his observations, a 4 1/2-inch refractor by Merz, and a 12-inch reflector. He acquired the latter instrument from Mr. N.E. Green, who had it constructed to his own design for the purposes of his observations of Mars in 1877…In 1860 Mr. Cottam married Mary Gibbs, of Kingsbury, who survives him, and he lived to celebrate their golden wedding a year before his death. They had one son and two daughters, of whom only the younger daughter is now living. His son died in March last, unexpectedly, after an operation, and there is no doubt that the shock of this loss hastened his own death…”.

The Entomologist: “It is with deep regret that we have to announce the death of Mr. Arthur Cottam, who passed away on November 23rd, 1911, at his residence, Furzebank, Bridgwater, in his seventy-fifth year, after an illness of some months' duration. As an entomologist he was perhaps better known to the past generation, as recently, owing to the weight of increasing years and failing health, he was not able to take such an active interest in the Lepidoptera and Coleoptera as formerly. His collection of Lepidoptera, the second which he had amassed during his lifetime, was sold at Messrs. Stevens's Auction Rooms only ten days before his death. From his young days he had been an ardent student not only of entomology but of botany, astronomy, and microscopy; and in January, 1875, he, with a few others, founded the Hertfordshire Natural History Society (at first called the Watford Natural History Society), and was its first Treasurer. He did some active work, and contributed several papers to the Transactions. For many years he was a Fellow of the Royal Astronomical Society, and published some useful star-maps. Music and art also claimed a good deal of his spare time, outdoor sketching being one of his favourite occupations at all times of the year. In 1905 Mr. Cottam retired from the Civil Service (Office of Woods and Forests) and went to live at Bridgwater. His love and all-round knowledge of Nature from many points of view, which he was always ready and anxious to impart to others, made him a most interesting companion, and the writer can recall many delightful excursions made in his company. He leaves a widow and one daughter to mourn his loss, his only son having died suddenly some nine months ago, after an operation”.

Journal of the Quekett Microscopical Club: “The Hon. Secretary regretted to have to announce the death, on November 23rd, at his home in Bridgwater, of Mr. Arthur Cottam, F.R.A.S., who joined the Club in 1869. Mr. Cottam had devoted much attention to the study of the genus Aulacodiscus, and in the astronomical world his name is well known as the author of the series of star-maps issued under the title of ‘Charts of the Constellations’ (1889). Mr. Earland said he had known Mr. Cottam at the time he lived at Watford. He was an excellent microscopist and a very skilful mounter, his chief subject being the Diatomaceae. He was perhaps better known as an astronomer, and had belonged to the R.A.S. for many years. He was also an excellent musician and a good painter. Like their late friend Mr. Jaques, he was connected with the Woods and Forests Department, and was a type of the best kind of Civil servant”.

Figure 7. Microphoscopic view of Cottam’s preparation of Niphobolus lingua fern scales, viewed between crossed polarizing filters.

Resources

Accounts and Papers of the House of Commons (1851) “Correspondence and Statements in Connexion with the Alterations in the Department of Woods, &c., Arthur Cottam…14th Junior Clerk”, page 84

Aclad, Arthur H.D. (1891) A Guide to the Choice of Books for Students & General Readers, Stanford, London, advertisement for Charts of the Constellations in the back of the book

http://www.algaebase.org/search/species/detail/?species_id=r5368897524a7cec2 (accessed January, 2015) Aulacodiscus africanus Cottam

Bracegirdle, Brian (1998) Microscopical Mounts and Mounters, Quekett Microscopical Club, London, pages 25, 128 and 182, & plates 12-G, 12-H, 12-J, 12-K, and 39-A

Cottam, Arthur (1866) Companion to Antares, Memoirs of the Royal Astronomical Society, Vol. 26, page 244

Cottam, Arthur (1875) Notes on the flora of the Watford District, Transactions of the Watford Natural History Society and Hertfordshire Field Club, Vol. 1, pages 14-16

Cottam, Arthur (1876) On a new Aulacodiscus, from the West Coast Of Africa, Journal of the Quekett Microscopical Club, Vol. 4, pages 149-153

Cottam, Arthur (1877) On the "autographic" process of lithography as applicable to the illustration of scientific papers, Journal of the Quekett Microscopical Club, Vol. 5, pages 6-8

Cottam, Arthur (1879) The micro-megascope, Transactions of the Watford Natural History Society and Hertfordshire Field Club, Vol. 2, page 242

Cottam, Arthur (1899) Stauropus Fagi at Watford and Ealing, The Entomologist, Vol. 32, page 237-238

Cottam, Arthur (1907) Notes on the habits of some of our lepidopterous insects - the butterflies, Transactions of the Hertfordshire Natural History Society, Vol. 11, pages 222-226

“Douglas” tree (accessed January, 2015) links associated with http://trees.ancestry.co.uk/tree/150060/person/7009469172

English census, birth, marriage, and death records, accessed through ancestry.co.uk

English Mechanic and World of Science (1889) Advertisement for Arthur Cottam’s Charts of the Constellations, Vol. 48, February 1, page x

English Mechanic and World of Science (1889) Report on the ninth annual meeting of the British Astronomical Association, Vol. 70, page 270

The Entomologist (1905) Lepidoptera in Hertfordshire, Vol. 38, pages 137-138

The Entomologist (1905) Lepidoptera in Hertfordshire in 1905, Vol. 39, pages 91-92

The Entomologist (1911) Obituary of Arthur Cottam, Vol. 45, page 48

The Entomologists Monthly Magazine (1911) Advertisement for auction of Arthur Cottam’s lepidoptera collection, New Series, Vol. 22, November issue, advertisements

The Gentleman’s Magazine (1849) Deaths: “Oct. 13. At his brother's, Blackheath, aged 43, Thomas William, second son of George Cottam, esq. of Camberwell”, Vol. 186, page 663

Hardwicke’s Science-Gossip (1875) Natural history &c. society at Watford, Vol. 11, page 41

Hardwicke’s Science-Gossip (1875) Convolvulus Hawk-moth, Vol. 11, page 277

Journal of the Quekett Microscopical Club (1876) Annual meeting, Vol. 4, pages 204-205

Journal of the Quekett Microscopical Club (1876) “Donations … Photograph of Mr. A. Cottam for the album”, Vol. 4, page 232

Journal of the Quekett Microscopical Club (1911) Obituary of Arthur Cottam, Second series, Vol. 11, page 454

Matthews, John (1879) On the micro-megascope, Journal of the Quekett Microscopical Club, Vol. 5, pages 167-169

Memoirs of the Royal Astronomical Society (1862) Election of Arthur Cottam, Vol. 22, page 97

“Milford-Cottam” tree (accessed January, 2015) links associated with http://trees.ancestry.co.uk/tree/4706733/person/1274467477

Monthly Microscopical Journal (1876) Watford Natural History Society, Vol. 15, pages 289-290

Monthly Notices of the Royal Astronomical Society (1911) Obituary of Arthur Cottam, Vol. 72, pages 248-249

Nature (1889) Large-scale charts of the constellations, Vol. 41, page 45

Nature (1911) Obituary of Arthur Cottam, Vol. 88, page 185

Probate of Arthur Cottam (1911) accessed through ancestry.co.uk

Transactions of the Watford Natural History Society and Hertfordshire Field Club (1878) Minutes of the Ordinary Meeting of March 10, Vol. 2, page xix

Transactions of the Watford Natural History Society and Hertfordshire Field Club (1878) Report of the Council for 1877, Vol. 2, page xvii

Transactions of the Watford Natural History Society and Hertfordshire Field Club (1879) Minutes of the Ordinary Meeting of June 12, Vol. 2, page lii