Botanical Instruments

Descriptive botany remained the benchmark by which botanists were measured well into the nineteenth century. When, after five successive failures, Charles Darwin was finally elected a corresponding member of the Académie des Sciences in Paris on 5 August 1878, he was surprised to find himself in the botany section rather than zoology. ‘It is funny’, he wrote to a friend, ‘the Academy having elected a … member in Botany, who does not know the characters of a single natural order.’Footnote ⁶ Despite his numerous botanical publications, Darwin did not regard himself as a botanist because he engaged in experimental physiological botany and had never done the taxonomic work regarded as fundamental to botanical expertise. Just a year earlier, he had complained to the American botanist Asa Gray that ‘It is dreadful work making out anything about dried flowers; I never look at one without feeling profound pity for all botanists, but I suppose you are used to it like eels to be skinned alive.’Footnote ⁷

The study of plant physiology depended upon intricate experimental set-ups involving apparatus of varying degrees of sophistication. Darwin’s son Horace, who undertook an engineering apprenticeship from 1875 to 1878, and established the Cambridge Scientific Instrument Company in 1881, devoted some of his earliest efforts to making instruments for his father’s botanical research.Footnote ⁸ These instruments were designed to record specific movements in plants, and were inspired by reports of the precision equipment in Julius Sachs’s botanical institute in Würzburg, where Horace’s brother Francis carried out research over the summer of 1878. After seeing a klinostat, designed by Sachs to measure the effect of gravity on plant growth, Francis told his father that it was ‘one machine we must have’. He also expressed his belief that Horace could design an instrument superior to Sachs’s, which was ‘far from well made’.Footnote ⁹ Francis’s confidence was probably based on the expertise Horace had displayed in 1876, when he had built an auxanometer – a self-recording instrument invented by Sachs for measuring the growth of a plant (Figure 5.2).Footnote ¹⁰

Figure 5.2 A self-recording auxanometer for measuring plant growth, made by Horace Darwin in 1876.

Image © Whipple Museum (Wh.2766).

This emphasis on apparatus, experiment, and measurement seems far removed from the observational taxonomic work Darwin believed marked a true botanist. However, earlier in the century, when floras had yet to be fully catalogued and taxonomic systems based on artificial characters were being challenged by ones based on natural affinities, the classification of plants also required instruments and a variety of manual skills.Footnote ¹¹ ‘I am become a passionate admirer of the Natural Orders as far as I yet understand them’, declared the botanist and future director of Kew Gardens William Jackson Hooker in 1816. Emphasising the ‘immense application’ that this study required, Hooker was also aware that he had an advantage over most other botanists: ‘I may thank my good fortune in having begun Botany with the Cryptogamia, which has given me a habit of dissection that I find of the utmost importance in the analysis of the flowers & fruits of the phænogamous plants.’Footnote ¹² Unlike phaenerogams (flowering plants), which were easy to classify using the artificial system of Linnaeus, cryptogams (non-flowering plants such as mosses, algae, and lichens) had long been regarded as some of the most complex groups of plants to order. Not only was their manner of reproduction puzzling and their family connections difficult to determine, but their minute size required the use of a microscope for the detection of the relevant characters by which their identity and affinities could be established.

In late 1816, Hooker was working with the Irish botanist Thomas Taylor on a monograph of British mosses, the Muscologia Britannica, which contained both written descriptions and illustrations of the plants at their natural size, with magnifications of the features by which they were classified (Figure 5.3). The skilful manipulation of a microscope, some artistic talent, and a competent engraver were essential to producing reliable information about these plants. But there was nothing easy or consistent about any of these stages. Not only did Hooker and Taylor drastically reduce the number of moss species, they also ‘declined quoting’ the illustrations in one of the standard floras of the period because they were so ‘excessively bad’.Footnote ¹³ The variability in quality of how these plants had been figured by earlier botanists, and the fact that illustrations embodied theoretical decisions concerning which characters were thought to define a species, made the use of dried specimens preferable, especially before the classification of mosses was fully established. An ‘admirably preserved & arranged’ moss specimen ‘is better distinguished than by the most elaborate figure’, Hooker stated in a private communication, and he and Taylor also declared this publicly in their illustrated monograph: although they emphasised the ‘utmost care’ with which their figures of mosses had been drawn, they admitted that well-prepared specimens were far superior ‘in point of accuracy to the best of plates’.Footnote ¹⁴ Hooker and Taylor did not refer to specimens in general but directed their readers’ attention to the Musci Britannici.

Figure 5.3 Plate 21 from W. J. Hooker and T. Taylor’s Muscologia Britannica (London, 1818), showing the magnified features by which mosses of the genera Zygodon and Orthotricum were identified.

Author’s copy.

Systematic botany has been characterised by Lorraine Daston as a process of identification and nomenclature, in which descriptions, illustrations, dried specimens, and actual plants are not interchangeable but interlocked. Descriptions and illustrations aimed to represent plants in general terms, emphasising only the essential characters that distinguished a species, while dried and growing plants conveyed the idiosyncracy of individuals, omitting none of their non-essential features. The interlocking of these elements of descriptive botany was essential both in the field and in the herbarium.Footnote ¹⁵ However, until a classification was stabilised through repeated and consensual observation, descriptions and illustrations were not regarded as reliable. The Musci Britannici was a key element in establishing the early-nineteenth-century order of mosses.

Making the Musci Britannici

The copy of Musci Britannici in the Whipple Museum must be one of the most unusual products of Eton College to end up in Cambridge. It was purchased in 1997 when the Eton College Natural History Museum sold this collection of mosses following the successful sale of several other sets of dried herbarium specimens.Footnote ¹⁶ The privileged provenance of this copy of Musci Britannici stands in stark contrast with the impoverished status of its maker, but in so doing it reflects the history of its production and distribution. It is one of about twenty-five sets made by Edward Hobson, a poor warehouseman in Manchester, in 1818. Hobson was born in Ancoats Lane, a working-class industrial area of Manchester, in 1782, but from the age of three was raised by an uncle in Ashton-under-Lyne following his father’s death and his mother’s subsequent alcoholism. First trained as a muslin weaver, by 1815 Hobson had become a warehouseman. From 1809, he had established friendships with other artisans in the area who collected plants, but it was Hobson who stimulated an interest in mosses.Footnote ¹⁷ In order to identify the mosses that they found, Hobson visited Chetham’s Library in Manchester to consult the most authoritative book on moss classification.Footnote ¹⁸ Unable to afford a microscope, the only instrument he had to examine his specimens was a ‘common pocket lens’.Footnote ¹⁹

When William Hooker and Thomas Taylor embarked on their monograph, mosses were regarded as fiendishly difficult – hard to see when growing, impossible to investigate without a microscope, and with no stable classification. Their study required exceptional powers of observation and, given how few botanists collected mosses, a dedication to obtaining specimens. In a botanical community consisting largely of private individuals, held together by correspondence, exchanges of specimens and information, and the bonds of friendship thus generated, the discovery of a keen observer, regardless of social class, was greeted with the same delight as the discovery of a rare plant. On hearing about a workingman whose particular skill lay in the ability to find mosses, Hooker therefore made a point of meeting Hobson for the first and only time in Manchester in 1815. Hobson, who had been allowed a couple of hours off from his work as a packer in a warehouse, delighted Hooker with ‘some very excellent mosses’ and by ‘how well he had named his specimens’. ‘I hardly ever saw a man possessed of more enthusiasm than this poor fellow’, Hooker declared soon after the meeting.Footnote ²⁰ By way of encouragement, he gave Hobson his Ellis aquatic microscope (Figure 5.4). The instrument had been Hooker’s ‘companion for many years’, which allowed him to know exactly what could be seen through such a microscope.Footnote ²¹

Figure 5.4 An Ellis-type aquatic microscope, similar to the microscope given to Edward Hobson by W. J. Hooker in 1815.

Image © Whipple Museum (Wh.1824).

Hobson not only supplied Hooker with fine specimens of rare and new species of mosses, but also, with Hooker’s encouragement and guidance, produced several sets of dried specimens for sale arranged according to Hooker and Taylor’s monograph, which was also published in 1818. In early-nineteenth-century Britain, when botany was pursued mainly by independent individuals scattered across the country, often with little or no access to the few public collections of note, herbaria were largely private collections. Moss specialists in particular collected in the field as much as they prepared and studied dried specimens in their cabinets in order to build up their collections, even if they also employed collectors to travel further afield. There was therefore a market for exsiccatae. Hobson’s Musci Britannici sold for £1, and was widely admired for its excellence and beauty. For Hobson, producing sets of specimens both enhanced his reputation and was a way of making some extra money.Footnote ²² The context of the making of the Musci Britannici clearly shows the interaction of patronage, commerce, polite exchange, and working-class participation in science.

The production of sets of specimens for sale reveals a division of labour and distinctions in intellectual or social status. Apart from the initial identification and arrangement of specimens, gentlemen botanists regarded the preparation of exsiccatae as unremunerative and time-consuming work, undertaken only when essential for the benefit of science. Hooker, for example, rejoiced in the public interest in the Reverend Miles Joseph Berkeley’s sets of fungus specimens, but regretted ‘the great manual labor [sic] you have in collecting & preparing the specimens’.Footnote ²³ In contrast, when the Scottish workingman Thomas Drummond began making extraordinary discoveries of mosses in Scotland, Hooker thought it entirely appropriate to encourage him, as he had Hobson, to prepare exsiccatae for sale. Aware that Drummond had a not very ‘creditable’ character, rather than send him money Hooker proposed to provide him with ‘five pounds worth of neatly done up books’ in which to fasten the specimens, and to take in return some copies of the work.Footnote ²⁴ Drummond was later sponsored to collect in America with the aim of making exsiccatae, but his sudden death in Cuba in 1835 left Hooker feeling obliged to ‘convert what specimens of plants are in hand into money’ for the benefit of Drummond’s family. To this end, Hooker recruited the help of the moss expert William Wilson in Warrington, who was willing to identify Drummond’s mosses but not to prepare the exsiccatae. Instead, he considered hiring ‘some neat handed female willing to work for 6^d or 1/– a day’ to fasten down the specimens, before persuading his wife to do the work.Footnote ²⁵

Wilson’s stress on neat-handedness in preparing exsiccatae is telling, and Hobson struggled more with the basic manual skills of laying down, ordering, and labelling specimens than might appear from his Musci Britannici. While Hooker acknowledged that he did ‘not know any Naturalist who has searched for Mosses more successfully than Hobson has done in their native stations, nor one who has discriminated them more accurately’, his efforts in bringing out Hobson’s work were directed largely to improving Hobson’s manual skills.Footnote ²⁶ From the very start of their exchange, Hooker had urged Hobson to take more care in drying specimens; he was still complaining in 1818 that ‘the specimens you have sent me if they were ever so rare are hardly fit for my herbarium the leaves are so twisted and muddled’.Footnote ²⁷ Hooker had also criticised Hobson’s preparation of a specimen that had arrived ‘so loaded with the earth on which it grows that I can hardly distinguish the fructification nor fasten it down in my herbarium’. In preparing exsiccatae, neatness was essential. Hooker sent Hobson a published set of Swiss mosses to act as a model, and suggested that Hobson

Hobson, acting on this advice, prepared a preliminary set of mosses which ‘much pleased’ Hooker, but also produced another spate of instructions. The paper must be thicker, the casings must accommodate the number of pages exactly, the pages must be cut ‘with an instrument at the Bookbinders’, the ribbands with which the casings were tied needed to be narrower, and the little bands of paper used to fasten down some mosses should be as small as possible and only used for woody stems. ‘I have sent a list of 100 arranged & named correctly’, Hooker told Hobson, suggesting he add ‘the places of growth to such as are not very common’. Two days later Hooker remembered to remind Hobson not to place his mosses in the same place on every page but to vary their positioning so that the pages lay flat in the case, to fasten them with ‘strong gum mixed with flour-paste’, and to enclose very minute ones in little cases of paper (Figure 5.5).Footnote ²⁹

Figure 5.5 Pages from Edward Hobson’s Musci Britannici showing (top) fixed moss specimens and (bottom) a small pocket containing loose specimens.

Image © Whipple Museum (Wh.4577).

Then there were the instructions for the labels. If Hobson did not think he could get the labels printed, Hooker pointedly suggested that perhaps ‘some friend’ could ‘write them in a good hand.’Footnote ³⁰ Neatness was an attribute much valued and noted by botanists, and included the labelling of specimens. Good handwriting was thus another manual skill necessary for the maintenance of a well-ordered collection. It was for the herbariums of expert cryptogamists and genteel collectors that the specimens in Musci Britannici were destined. Hobson chose to have his labels printed.

The Publication Circuit

The ability to produce multiple sets of the same plants was limited by the quantity of the rarest specimen.Footnote ³¹ It was therefore essential to build up stocks of specimens before embarking on the sale of exsiccatae. However, given the time-consuming labour of producing sets of specimens as well as the costs involved in printing labels and buying paper and cases, it was also important that Hobson, before starting work, acquired subscribers for the Musci Britannici to ensure that he made ‘no more than are spoken for’.Footnote ³² ‘I will do all I can (if you determine upon it) to recommend it’, Hooker assured Hobson, ‘& will mention it in my Muscologia, which is now about to appear.’Footnote ³³ Hooker and Taylor announced Hobson’s intention to produce exsiccatae, pointing out how much more accurate and how much cheaper sets of specimens were than plates.Footnote ³⁴ The orders began to flow in.

But this was not all that flowed in. Both specialists and enthusiasts began to offer Hobson mosses. The production and distribution of the Music Britannici thus reveals how even a commercial enterprise was dependent on the system of knowledge and specimen exchange built up through correspondence networks for mutual benefit of all participants. ‘I shall be very glad at any time to supply you with any specimens in my power, that may be likely to be of service to you’, the botanist and clergyman William Bree told Hobson after purchasing his copy of Musci Britannici and ordering two more copies for Warwickshire botanists.Footnote ³⁵ Edinburgh botanist Robert Kaye Greville placed an order after he had seen his friend John Stewart’s copy of Hobson’s ‘valuable work’, offering at the same time a good stock of some specimens.Footnote ³⁶ Greville continued to supply Hobson with specimens, and by 1820 hoped that what he sent might ‘hasten the appearance of a second volume’.Footnote ³⁷ Stewart, a botanical lecturer in Edinburgh, also offered to help Hobson, and commented that anyone in Edinburgh acquainted with cryptogamic botany was ‘quite delighted’ with the Musci Britannici.Footnote ³⁸ Hooker’s close friend and keen muscologist Charles Lyell (father of the geologist) sent choice specimens to Hobson, and also hoped that the demand for the first volume would encourage Hobson to publish another volume very speedily.Footnote ³⁹ Susannah Corrie of Woodville near Birmingham regretted she was prevented by illness from sending more specimens, while the plant collector Margaret Stovin of Derbyshire wondered how Hobson made the time ‘with other necessary avocations to compleat so beautiful a work’.Footnote ⁴⁰

Time was the crucial issue. Hooker thought that preparing moss exsiccatae might be a way for Hobson to earn ‘a few shillings’, but acknowledged that Hobson alone could judge the ‘value’ of his time and whether it was worth undertaking such work.Footnote ⁴¹ As demand for the first volume of Musci Britannici grew, Hobson himself began to express concern that making up the volumes was so time-consuming that it left him little opportunity to collect mosses. It was only with the help of Hooker and Lyell in particular that Hobson was able to complete twenty-five copies of the first volume and then embark on twenty sets of a second volume.Footnote ⁴² However, progress was so slow that the naturalist John Edward Gray, then an assistant in the British Museum, wrote to the botanist Roberts Leyland of Halifax in July 1822 to enquire whether he knew ‘Mr. Hobson the author of the Musci Brittanici, a most excellent collection of British specimens of Mosses’. ‘I have his first part & wrote directly for the second, but I have [not] heard any thing from him & have lost his Direction,’ Gray explained to Leyland.Footnote ⁴³ By this time, Hobson had, in fact, begun preparing his second volume, and Hooker was one of the first to receive a copy in 1822. Declaring himself ‘much pleased’ with the ‘very interesting volume’, Hooker urged Hobson to supply as quickly as possible copies to the purchasers of the first volume who wished to buy the second.Footnote ⁴⁴

The publication of a second edition of Hooker and Taylor’s Muscologia Britannica in 1827, detailing some newly discovered species, prompted Hobson to consider a third volume of Musci Britannici. At this point it was not time that Hobson lacked but specimens, as he explained to Hooker: ‘In consequence of the Bankruptcy of my late Master … I am now out of employment for some time and should have time to go on with a third Vol^m. of British Mosses &c if I had sufficient quantity of some species that are mentioned in the annexed list.’Footnote ⁴⁵ On this occasion, however, Hooker was discouraging. He did not possess sufficient specimens himself and did not think Hobson could obtain adequate supplies to make up volumes ‘without great delay’; instead he suggested that the volume be devoted to cryptogams more generally and also mentioned that Hobson could obtain Scottish mosses by ‘entering into an exchange’ with Hooker’s Scottish protégé, Thomas Drummond.Footnote ⁴⁶

The production of Hobson’s Musci Britannici shows that, even as a commercial object, it depended upon the networks of polite exchange. But it is important to recognise just what was being purchased. It was not the case that gentlemen like Lyell provided Hobson with specimens that were then sold back to them. The principle of gift exchange in natural history with respect to specimens and knowledge was not violated.Footnote ⁴⁷ Rather, what was being paid for was the manual labour involved in making exsiccatae and the quality of the specimens included therein. This was especially the case with species that were difficult to find ‘in fruit’, that is with the capsules that were essential to identifying some species of moss. The difficulties of collecting sufficient fruiting plants, the time-consuming fixing of specimens, and the system of payment may have made preparing exsiccatae unappealing to gentlemen botanists, but such work did not threaten the norms of exchange networks.

Conclusion: Exsiccatae Unbound

The role of different observational tools for seeing in botany is exemplified in the early career of William Hooker’s son Joseph. When Joseph Hooker set off as assistant surgeon and ship’s botanist on an expedition to the southern oceans and Antarctica, his ambitions included describing a genus of mosses for his first paper at the Linnean Society of London.Footnote ⁴⁸ Conditions were hardly favourable. In rough icy seas often ‘he & his microscope had to be lashed to the table from the rolling of the ship’.Footnote ⁴⁹ Nonetheless, Joseph managed to produce copious drawings of highly magnified dissections that were essential for identification. His appreciation of the rationale behind the classification of this difficult group of plants had, however, been formed much earlier through exsiccatae.Footnote ⁵⁰ In the calmer waters of Berkeley Sound, Falkland Islands, he received a reminder of what had inspired his love of mosses. His father had sent him, half way round the world, the recently published ‘Memoir of Mr. Edward Hobson’.Footnote ⁵¹ Although Joseph regarded himself ‘a born Muscologist’ because both his mother and his father independently began their botanical studies with the mosses, his latent powers were, he claimed, stimulated ‘by a book in my father’s library … by Edward Hobson, of Manchester’.Footnote ⁵² The Musci Britannici probably remained part of William Hooker’s library until his death in 1865, when his cryptogamic collections, his private property up to this point, were sold to the Royal Botanic Gardens at Kew, where he had served as director from 1840.

The Yorkshire botanist and clergyman James Dalton, Joseph Hooker’s godfather and William Hooker’s close friend, probably kept his copy of Hobson’s Musci Britannici in his library too. But this presented Dalton with a dilemma when he decided to donate his moss herbarium to the York Philosophical Society. He wished to include the mosses prepared by Hobson in his collection as they possessed ‘the authority of a good Muscologist’. There was only one solution. Dalton hoped that Hobson would not be ‘offended’ by his ‘begging to be considered a purchaser’ of another set of specimens because he could not bear to break up the ‘beautiful’ set he had already received.Footnote ⁵³ Moreover, for those actively studying mosses, dissection of specimens was often essential; for this reason the Irish botanist Thomas Taylor had asked for duplicates of Drummond’s American mosses ‘in order that he might be able to preserve the published spec^ms. from mutilation’.Footnote ⁵⁴

Hobson’s Musci Britannici was an observational tool. Yet, from the perspective of the present, it is all too easy to regard it only as a self-explanatory taxonomic exercise showing how a particular group of plants was classified at a specific point in time. Hobson’s Musci Britannici is thus taken to represent the end point of a collection rather than a stimulus to observation. Many of the copies in public institutions reinforce this notion. Where preserved in libraries, the scientific relevance of the Musci Britannici has dwindled to little more than a collection of specimens trapped in an obsolete taxonomic system. The most extreme case is the copy in Chetham’s Library, Manchester, which has been bound as a book. In contrast, when found in herbariums, the pages of Musci Britannici are either dispersed among the larger collection of plants, or, if kept in their covers, reordered by later users who have arranged and renamed the specimens according to more recent classifications.Footnote ⁵⁵ Even those copies that remain in their original format relatively intact, like the copy in the Whipple Museum, no longer explicitly impart their function as a method for learning how to observe. It is by considering both production and consumption that the Musci Britannici shows its potential as an instrument of observation. The point of exsiccatae was not only to convey a systematic understanding of difficult groups of plants, but also to hone observational skills by guiding and training the eye. The publication of specimens labelled with their species names and arranged into genera provided a way for the botanical community to calibrate its vision and test new classifications.