Although historians have recently shown a great deal of interest in the early-modern search for the liquor alkahest or universal solvent, early Royal Society discussions of that legendary substance have been ignored, probably because the papers associated with them seemed to have been lost. Three of them have recently been rediscovered in the Society's archives. This article reproduces them for the first time in photographic facsimile with a description and commentary placing them in their contemporary context.
Alkahest in early Royal Society Minutes
Four Minutes of the Royal Society from 1661 record discussions involving the liquor alkahest, the universal solvent sought so eagerly at that time and well into the next century. Despite a resurgence of interest in the alkahest over the past few decades among science historians, these Minutes have attracted little attention. That is probably because although the Minutes mention papers read at the corresponding sessions, these have disappeared from scholarly view for a long time.
Some of these papers have now been rediscovered by two of us (A.M.A.-G. and M.H.M.F) while researching the Royal Society archives as part of a project on the development of historical ideas on material principles. Their work had come to focus on the papers of an active member of the Society during its earliest years, namely Jonathan Goddard (1617–75). Cross-checking his memoirs and other writings against the Minutes of the Royal Society provided clues that eventually led to the recovery of documents on the alkahest and its putative animal counterpart.
Various problems encountered in searching for those papers and in identifying the author of the first paper are described in the last section, which, it is hoped, may both stimulate other researchers and provide helpful guidance for further work on the Society's archives. Once the problems were overcome, it became easier to place the recovered documents in their contemporary scientific and cultural context and to reconstruct the subject of the discussions.
The Minutes recording the ‘animal alkahest’ meetings state:
Oct. 16, 1661 MR. OLDENBURG read a paper concerning a liquor to be had out of animals like the alkahest; which was referred to the physicians of the society.
Oct. 23, 1661 It was ordered, that it be referred to Dr. GODDARD, to make inquiries about the liquor of animals like the alkahest.
Oct. 30, 1661 Dr. GODDARD delivered in inquiries concerning the liquor Alkahest, made of animals; and they were ordered to be fairly written, and given to Mr. OLDENBURG.
The session's Minute makes a discrete allusion to another document, discussed perhaps that same day: ‘It was ordered, that the description of the liquor alkahest be transcribed and kept.’
Nov. 13, 1661 Mr. OLDENBURG brought in an answer to Dr. GODDARD's queries concerning the liquor alkahest of animals.1
Three of the documents mentioned in the Minutes have now been recovered. The first one is the paper read in October 1661 by Oldenburg, and makes a novel link, scarcely noticed in secondary literature, between the alkahest and a fluid found to be present in the newly discovered lymphatic vessels. The paper purported to give experimental support for that claim, in keeping with the Society's motto, ‘Nullius in verba’. The second document presents the ‘Queries’ drawn up by Goddard, raising doubts about the experiments and the conclusions that had been drawn from them. The third document is a description and recipe for preparing the liquor alkahest and provides a basis for the analogy proposed in the first paper.2
Two Fellows were mentioned in the Minutes as participating in the Royal Society discussions. One was Henry Oldenburg (ca. 1619–77), Secretary of the Royal Society; the other was Dr Jonathan Goddard.
Oldenburg's first appointment in England was as the diplomatic agent of his native city of Bremen to the court of Cromwell during the Protectorate (1653–59). He met Lady Ranelagh, a sister of Robert Boyle, and was appointed tutor to her son Richard Jones. While accompanying Richard during his year at Oxford, Robert Boyle secured Oldenburg entry into the scientific group that flourished there under the patronage of John Wilkins of Wadham College. Oldenburg continued to concern himself with scientific matters when he guided Richard during his continental grand tour and sojourns, and maintained close contact with Robert through his letters.3 After his appointment as Secretary of the Royal Society in 1662, he began a vast correspondence at home and abroad, and the publication of Philosophical Transactions from 1665 until his sudden death in 1677.
Goddard4 had been an active member of the Oxford group. He moved to London on being appointed to a chair at Gresham College by the Lord Protector, Oliver Cromwell, whom he had served as personal physician. Although replaced by a royalist appointee at the Restoration, he was chosen as a Council member in both royal charters (1662 and 1663) granted to the Royal Society. Goddard was particularly interested in new scientific instruments, in particular the microscope and the telescope, and at Oxford in the Torricellian tube and the air-pump. He had an extensive collection of chemical apparatus and had engaged an operator in his house, which made his rooms at Gresham College particularly convenient for the earliest meetings of one of the several ‘precursor’ groups that led to the foundation of the Royal Society at the Restoration. Birch noted his active participation in almost every meeting of the Society, remarking that he was a ‘good practical chemist’ and his services were ‘always at the beck and call for the investigation of curious problems.’5
However, the name of a third person, who (as we shall show) wrote the paper read by Oldenburg to the Society in October 1661, was not recorded in the Minutes. What light do the new documents cast on his identity?
Author of the ‘animal alkahest’ paper
Added at the top of the paper is a name, which ought to have made it easy to identify him. However, a Royal Society cataloguer had at some date read it as ‘Catharys med. germ’ and had filed the document accordingly.6 The search for a physician of that name proved unrewarding and our close analysis eventually led to a different reading: that of ‘D[ominus] Colhans’ or ‘Master Colhans.’ Further research, plagued with difficulties at every turn, permitted us to identify Colhans (with variants of ‘Kolhans’ or ‘Kohlhans’) as Tobias Ludwig Kohlhans (1624–1705).7
Who was T. L. Kohlhans, and where and how did Oldenburg first encounter him?
T. L. Kohlhans's name is much more familiar to historians of religion than to those of medicine or science. A biographical search plunges us immediately into the central Europe of the mid seventeenth century, attempting to repair the physical and social devastation inflicted by the Thirty Years’ War (1618–48). When Duke Christian August of Sulzbach in Bavaria recovered his lands and resumed his ducal reign (1645–1708), he had lost an estimated three out of five of the original inhabitants. He repopulated his ducal lands by inviting Jews and other displaced groups, and, after his conversion to Catholicism in 1652, his co-religionists. However, he continued to implement an irenic religious policy, insisting on strict parity of resources and facilities between the major denominations. In planning and implementing that policy he was advised by a European circle of intellectuals. Its most prominent member was Francis Mercurius van Helmont (1614–99), a son of Joan Baptist van Helmont. Francis, in turn, seems to have attracted T. L. Kohlhans to Sulzbach and they became close friends. Kohlhans brought with him diplomatic skills and contacts and a medical qualification. He soon won the duke's trust. In 1658 he was appointed physician and political adviser to him and continued in that post for the next 10 years.8
The title of royal physician was by no means a courtesy one conferred on Kohlhans. He had obtained a medical degree at the University of Heidelberg.9 The medical faculty included Jacob Israel (1621–74), who had presided over his examination. In his dissertation10 Kohlhans displayed a very competent knowledge of the latest advances in physiology and pathology, and a personal acquaintance with some of the leading anatomical researchers at Leiden University, notably Johannes van Horne or Hornius (1621–70), who belonged to the distinguished circle of Leiden anatomists associated with the discovery of the lymphatic ducts and vessels. Horne was probably a defining influence on Kohlhans's interest in lymphatics, and they must have met while the latter spent some time at the medical school of Leiden before moving first to Königsberg and finally to Heidelberg for his medical qualification.11
As for Oldenburg, he had been meeting members of Christian August's circle since 1658, and probably again between the autumn of 1661 and the spring of 1662. Francis Mercurius may himself have visited England shortly before that, but without attracting much attention in the extant historical records.12 It can safely be established, however, that Kohlhans himself was in England at the time of the Royal Society discussions and was in close contact with Oldenburg before returning to mainland Europe in March 1662. Evidence for this was supplied by Oldenburg himself when he wrote to Christiaan Huygens in that same year:
Mr. Kohlhans, who brings you this, is a Doctor of Medicine returning to Germany and eager to meet the learned and inquiring men of the Hague. I thought I should direct him to you and entreat you to receive him with the same kindness that you were so good as to bestow upon me when I had the honour to see you last summer ….13
Oldenburg went on to request Huygens to display to Kohlhans some of the devices and experiments he had demonstrated at Gresham College during the previous year, when attending the coronation of King Charles II.14 The letter ends abruptly, with the excuse that Kohlhans had just then arrived to collect the letter and to bid his farewells.15
Furthermore, our researches now indicate that Oldenburg considered the paper he had read to the Society on the lymphatic system and the alkahest important enough to be attached to a letter to his patron, Robert Boyle, at about the same time, alerting him to the presence of its author in England.16 Although Oldenburg had once again omitted any mention of the source of this novel and curious idea of an ‘animal alkahest’, he mentioned a certain ‘stranger’,
… wch is a hard student in Physick and Chymistry, and a great friend to that Philosophy, yt explicates things by mechanicall and intelligible principles, will be very glad to heare yr objections against his Menstruum, and will be found, I think, pretty ready to satisfy some of ym [them]; though he pretends not, to make yt liquor to be ye same with the Grand Alkahest, but analogous thereunto.17
Oldenburg's activities indicate a lively interest in the alkahest at the early Royal Society. When he heard rumours of an ‘animal alkahest’ during what proved to be his last journey to mainland Europe, he followed it up with a paper he read to the Society, probably taking advantage of the visit by the author himself to England at the time.
Before examining the documents in more detail, we shall consider why the universal solvent had been the object of so much interest throughout Europe at that time. Because Kohlhans claimed the existence of an analogue for it in animal bodies, we shall also briefly sketch the course of the new anatomical discoveries involving lymphatics and lacteals and their associated vessels and fluids.
Origins and development of the ‘Liquor Alkahest’
The quest for a legendary universal solvent, identified by J. B. van Helmont with the alkahest first mentioned by Paracelsus, assumed great importance through the seventeenth and even into the eighteenth century. It secured the intense interest not only of alchemists and post-Paracelsian iatrochemists, but also of those pioneering a new corpuscular and mechanistic matter theory, from Boyle down to Hermann Boerhaave. In The Sceptical Chymist (1661), Boyle recalled the claims made more than once by the elder van Helmont that, like his predecessor Paracelsus, he too possessed ‘the famous Liquor, Alkahest’, to which he gave another name, the ignis gehennae, since it reduced bodies that resisted ‘Vulgar Fires’ into their primary constituents, adding:
To this Liquor he ascribes, (and that in great part upon his own Experience) such wonders, that if we suppose them all true, I am so much the more a Friend to Knowledge than to Wealth, that I should think the Alkahest a nobler and more desirable Secret than the Philosopher's Stone it self.18
A similar claim was repeated more than half a century later by Boerhaave, in his famous textbook Elementa Chymiae (1732). If anyone had really possessed the alkahest, as ‘solemnly’ affirmed by van Helmont, then it must be called ‘the most valuable discovery ever yet made in chemistry or in any other art’. The liquor alkahest was ‘of greater consequence, and more to be desired, than the philosopher's stone’, because it made it easy to procure both riches and ‘the most efficacious remedies’ for bodily ills.19
Paracelsus and then Helmont and the Helmontians had shifted the alchemical aim from metallic transmutation to that of providing more powerful remedies than any hitherto known for all diseases. The preparation of the alkahest consequently became their most sought-after goal, because it was reputed to recover the primary constituents of a body, including the seminal virtues in which resided their therapeutic efficacy, in its purest form.20 An example was the belief that by dissolving a mineral called Ludus with the alkahest a remedy could be obtained for urinary calculi, a condition then held to be incurable.
We have confirmation in a letter to John Winthrop, governor of Massachusetts, of 16 March 1660 by Samuel Hartlib that his own chief interest in the alkahest was due to its medical efficacy, in particular for a ‘stone in the bladder’, which he believed was the main source of all his bodily pains. He referred to the Alkahest Elixir which had been promised but never delivered by J. R. Glauber, and remarked, ‘I hope you will bear with me if I tell you that some [that] are related unto me, that have really such a secret as Helmont hath described under the name of liquor Alkahest.’21 Hartlib's remarks remind us of the considerable overlap of interests and outlook between Oldenburg and the Hartlib group at that time and shed more light on Oldenburg's initiating the ‘animal alkahest’ meetings and his participating actively in them.
Lacteals and lymphatic vessels: challenges for Galenic physiology
Kohlhans and Goddard were each engaged actively in the project for a new physiology and pathology to replace the Galenic one as it was increasingly discredited by the advances in anatomical dissection, both human and animal, and by the emergence of new approaches for studying and explaining the workings of the body in health and disease. It was directly related to the developments in anatomy, in particular the doctrine of blood circulation proposed by William Harvey (1628), followed at the mid-century by the discovery of an entirely unknown system of vessels and fluids that called into question the Galenic doctrine of nutrition and sanguification.22 It undermined in particular the importance granted to the liver and the lowly status of the spleen in the Galenic schema. The Oxford and London groups to which Goddard had belonged were concerned with the consequences of these advances.23 The two earliest publications of Kohlhans, too, dealt with two important Galenic doctrines: the first was the inaugural dissertation submitted for his medical degree at Heidelberg University, on the nature and function of the spleen, and the second, in the form of a letter, took as its subject the animal spirits.24
Galen's account of the spleen had been the subject of debate since the sixteenth century, as the medical humanism that led to the recovery of the Galenic texts in the original Greek led also to greater acquaintance with a somewhat different one in an even older authority, Aristotle. According to Galen, the spleen removed an impurity when chyle, made from aliment as it passed from the stomach to the guts, was transformed into blood in the liver. Just as wine, made by the fermentation of grape juice, left behind a residue, so too did the generation of blood in the liver from the chyle in the guts. The lighter impurity was drawn away by the gall bladder as yellow choler, and the thicker and more ‘earthy’ one by the spleen, as the melancholic humour. Aristotle, by contrast, had regarded the spleen as serving a purpose on the left side of the body analogous to that of the liver on the right side, and the new textbooks on anatomy in the later sixteenth century took notice of the controversy, while reaffirming the superiority of the Galenic doctrine.25
The controversy over these different views intensified with the advance of anatomical discovery after Andreas Vesalius (1514–64), and challenged the pre-eminent role assigned to the liver in the Galenic schema. Harvey's theory of blood circulation, supported by anatomical evidence, no longer required the liver to supply new blood continually as the nutritive process consumed it. An even greater blow to the Galenic account of the liver was struck by the discovery that chyle did not pass from the intestines to the liver but to a new system of vessels that drained eventually through the portal vein into the general circulation. With it came a reversion to the Aristotelian view of the heart as the centre of blood generation,26 and of the spleen as assisting it in the purification of arterial blood (an opinion reflected in the Royal Society's Kohlhans manuscript).
Quite apart from the new discoveries of blood and circulation and the new vessels, van Helmont had put forward his radical views concerning digestion and nutrition. He had replaced the dominant place of the liver in digestion and nutrition by a ‘duumvirate’ of the stomach and the spleen, and posited an acid gastric liquor in the stomach.27 Moreover, van Helmont had contrasted digestion with the action of medicines on human bodies: the former led to a transmutation and assimilation of nutritive substance, whereas medicines acted without undergoing any substantial change themselves.28
Kohlhans's dissertation carefully considered the historical developments that had undermined the Galenic account of the nature and function of the spleen. It was in the Appendix supplementing the discussion that he first presented his novel idea of the lymphatic fluid as an ‘animal alkahest’ or at least an analogue of the Helmontian universal solvent in animal bodies. In the main part of the dissertation he stated that he neither accepted nor rejected Helmont's opinions on the spleen but had formed conclusions much more in agreement with those of Waleus and Hoghelande, among several others.29 They were that the spleen drew particles of blood through the splenic artery and, after mixing them with its own substance, turned them into an acid liquor by attenuation and rarefaction. Sent through the splenic vein into the portal vein, the acid humour assisted the processes by which the blood fermented and generated spirit in the liver, and stimulated appetite and the production of chyle in the stomach. It then passed through the renal arteries to the kidneys, from whence, mixed with a serous excrementitious humour, it was excreted with the urine.30
Helmont's influence was more prominent and Kohlhans's originality more evident in the Appendix to the dissertation on the spleen in which he introduced the novel idea of the alkahest or its analogue being present in the newly discovered vessels, whose function was to extract the ‘seminials’ from the chyle prepared in the gut. The paper that Oldenburg read at the meeting of the Royal Society on 16 October 1661 must therefore be considered a summary drawn from the Appendix to Kohlhans's academic dissertation at Heidelberg.
Whereas the Appendix reflected the joint influence of the new anatomical discoveries and of Helmontian doctrines, the letter on the animal spirits may be said to form a bridge between Helmont and the mechanistic physiology of Descartes. Descartes had described the animal spirits as ‘a very fine wind, or rather a very lively and pure flame’.31 Kohlhans suggested that they were composed of particles of the most subtle first matter of Descartes, with the Sun as its locus, and sketched a grand theory of the action of light in the three kingdoms of nature, which aimed at reconciling the doctrines of Descartes and Helmont.
Both publications constitute a striking confirmation of Oldenburg's letter to Boyle, quoted earlier, that Kohlhans was ‘a great friend to that Philosophy, yt explicates things by mechanicall and intelligible principles …’ but had an equal interest in Helmontian doctrines and themes, notably the alkahest. In this attempt to reconcile what we may now see as diverging and even incompatible approaches to the study and explanation of natural phenomena he was at one with the Dutch Cartesians that he mentioned approvingly, namely Hoghelande and De Raey, and similar to the most famous of seventeenth-century mediators, Leibniz, in whose correspondence he appears from time to time. Although Kohlhans seems to disappear from the literature of science and medicine after these publications, he acted as a conciliator, again like Leibniz, by mediating in the aftermath of the Thirty Years’ War between hostile factions in the sphere of religion and confessional politics, initially at the court of Christian August in the company of the younger Helmont and Knorr von Rosenroth, and continued to do so until the very end of his life.32
Royal Society document on the alkahest
Many Helmontian ideas and themes are reflected in the Royal Society manuscript33 on the liquor alkahest and its preparation (figures 1 and 2), as well as several Paracelsian ones that Helmont had expressly rejected.
The manuscript began with a succession of synonyms for the alkahest in Helmont's tracts, describing its nature and powers. The alkahest was called ‘immortal’ in the very title of the manuscript, because it was believed that it never lost its power as a universal solvent, however many times it had been used.34 It was the ‘Maccabean fire’ because Helmont detected a resemblance between the ‘cold fire’ of the alkahest and the ‘thick water’ mentioned in the Book of Maccabees in the Old Testament.35 It was called latex, or clear water ‘reduced to its minutest atoms’36, and even the Primum Ens Salum, or salt exalted to its highest degree.37
The author then disclosed that the basic material to be used was human urine, and discussed why that was so, using the ancient and medieval parallelism between the macrocosm of the Universe and the microcosm of man. Urine contained in itself all the forms and powers of the greater world, man being ‘the true System of the Universe’. Man could be represented by the numerals one, three and seven: one, because he was a self-subsistent individual; three, because he contained body, soul and spirit, and the tria prima of salt, sulphur and mercury; and seven, because he possessed the seven powers of the seven elements from the seven spirits of God.
The manuscript then introduced a genuinely Helmontian concept in its justificatory arguments. It asserted that, besides the characteristics comprised in the numbers one, three and seven, which man shared with other bodies, he was also endowed with a ‘Lunar Blas’, which was a ‘cold Spirit or Mercury’. ‘Blas’, like the term ‘gas’, was a term introduced by Helmont to describe principles of ‘motion’ (change and alteration) in the world.38 The manuscript stated that it possessed a cold fire, a celestial quality, contrary to all hot sulphurs and salts. After being subjected to circulation, putrefaction and exaltation, it conferred on the alkahest the power to divide the corporeal form or matter of all bodies, which was saline, into its principles, while preventing the alkahest from ‘radically’ uniting with any other body, and fleeing from it as soon as it had accomplished its work.
After this justification for the prominent role given to urine in its preparation, the manuscript provided a recipe for the alkahest. It involved filtration followed by distillation of stale urine for about seven or eight days in a gentle heat. After the spirit was drawn off, the residue was allowed to settle at the bottom of the vessel and was described as a ‘limosity’ and the ‘magnet of man’. When a sufficient quantity had accumulated, it was to be ‘imbibed’ in its own spirit and, when the two had united, subjected to an operation in a pelican (for reflux distillation) until it ‘shoots off’ crystals; it was allowed to do so until that process came to an end. The crystals were then ‘imbibed’ with ‘Diana's doves’ until they swelled up.39 They were then transferred to a transparent vessel, which was hermetically sealed, and putrefied in a balneum mariae until they united perfectly, which could take about 50 days. The mixture was then drawn off and was ready for use.
The note that concludes the document introduced a qualification to some of the claims made in the preceding sections. It referred to the author's ‘present opinion’ that nothing ought to be used but human urine and only by ‘mediation’ of Diana's doves, adding a further justification in favour of that opinion. It was better to use stale and ‘fermented’ rather than fresh urine, because the former decomposed readily into the tria prima. The residue that settled to the bottom of the vessel, and what was left in the filter, was the salt present in the ‘concretes’ we eat and hence differed in no respect from common salt. The first spirit to separate itself was the ‘Mercurial part’, as evident from the fact that it coagulated when treated with spirit of wine (alcohol) to which common sal ammoniac had been added, and it was no other than the ‘volatile salt’ of all concrete bodies.
Overall, the document reveals a somewhat eclectic combination of Helmontian and Paracelsian ideas. Many of the terms that Helmont had used for the alkahest were invoked, but so were Paracelsian motifs that Helmont had vehemently rejected. This was notably so in the use of the microcosm–macrocosm analogy to justify the choice of human urine as the basic material.40 The ‘magnet of man’ and ‘limosity’ may refer to the Paracelsian belief that man was made of the same elements as the Universe, and hence there was an act of sympathetic attraction between an outside object and its inner representative in man.41 That was again a way of thinking that pervaded Paracelsus's works, but it was uncongenial to Helmont.42
So, too, would have been the invocation of the tria prima as the primary constituents of bodies, demonstrated by subjecting a substance to ‘fire analysis’ or distillation. Helmont was well known for his argument that the three elements did not pre-exist in a body but were products resulting from subjection to fire or to the process of distillation.43 He insisted that the task of analysis could best be performed by the universal solvent, and when it divided bodies into their primary constituents they would by no means be the Paracelsian three ‘principles’. Moreover, although famous for introducing quantification into natural enquiries, as in his willow-tree experiment, Helmont discouraged the numerological use of numbers, such as the one, three and seven used in the Royal Society manuscript to define man's relation to the Universe.44
Kohlhans on the ‘animal alkahest’
If it is granted that there exists a liquor alkahest, which can resolve all tangible bodies, even coal and stones, into a creamy liquor, after extracting their essential ‘nature’, and which, when drawn away, resumes its original state, with respect to quantity and quality, then something analogous, if not the very same, seems to be present in all animal bodies. It is to be found in their lymphatic and chyliferous vessels, and present in abundance in the channel that commences its ascent by the psoas muscle. These vessels differ only in the diversity of the matter they contain, and that depends in turn on the emptiness or fullness of the ventricle.
When the [gastric] ventricle is empty, the vessels contain a pure and pleasantly acidic fluid, but coral stones soaked overnight in a small quantity of it lose their intensely red colour and become friable. When the ventricle is full, however, that liquor separates itself and combines with what is best in ingested food and drink and turns it into a milky fluid. That mixture then enters the lacteal veins and continues to the right side of the heart, where what has been separated is turned into blood and is conveyed by the circulations of the blood to the various parts of the body and the viscera. After depositing what it carries, the liquor then separates itself and regains its original perfection both in quantity and quality.
Goddard's queries on Kohlhans's ‘experimentum’
In his queries (figures 5 and 6),45 Goddard raised particular doubts about the contentions, first, that the lymphatic and chyliferous vessels contain an acidic fluid and second that the fluid is analogous to the ‘alkahest’. Goddard pointed out that, in his description of the fluid when he first published his discovery of the lymphatic vessels, Thomas Bartholin had assumed that it was ‘meer water’, and hence named it ‘lymph’. That fluid was quite distinct from any ‘serose, acidic, or acrimonious humour’, whose transport was assigned to other organs, such as the gall bladder and the urinary parts. None of those who had subsequently written on the lymphatic vessels had dissented from that judgement. So a doubt had to be raised about the claim that the liquor contained in this kind of vessel had ‘any such Acidity’.
If that acidity was observed after a long period of fasting, then it could be accounted for by a number of well-known facts. Any liquor sweetened by sugar, honey or ‘milky sweetness’ turned acidic, unless a good proportion of ‘vinose or other potent spirit’ had been added to it. Fasting, moreover, was known to increase ‘acrimony’ in the blood and the humours of the body, because the more volatile portions would already have separated themselves and been dissipated. Ought not a satisfactory account of any observed acidity in the fluid be attributed to those causes, rather than to ‘the separation and mixture of one and the same “seminal” acid matter from and with all the aliment conveyed daily into the body’?
To these objections Goddard added another consideration. If such a liquor were present in the body, it would vary according to the age of the animal concerned. The quantity of it present in an adult would then be 10–20 times more than in a newborn creature. In that case, the liquor was capable both of generation and augmentation over time. But nothing, then, could prevent it also from being corruptible, and in a constant state of diminution and reparation. But then it could not be said to differ in any important respect from the other humours present in the body. Goddard gave examples of a regenerating process, similar to that ascribed to the liquor, from baking and brewing. In the mass of dough for making bread, a small part was usually set aside, salted and prevented from drying or corruption. It then acquired acidity and became suitable for making the next batch of bread. Similarly, part of a newly brewed drink could be used for fermenting the next one. It would be as effectual as the first one and in no way required the separation from it of a seminal ferment to continue the brewing process.
Goddard also raised questions about the corals soaked in the liquor: how large were they? Was their colour altered superficially or ‘throughout’? Acids commonly ‘more or less’ dissolved coral, which then lost its colour, but without the menstruum acquiring it. The liquor described in the paper must possess the ‘peculiar property’ of dissolving the alimentary matter in animals or of extracting what the body needed from it. Had the liquor been applied to specific items of food eaten by particular animals and, if so, with what degree of success? Since food was found to remain solid and fleshy in the bowels of animals, did the liquor dissolve it as a whole, or did it at least extract a milky liquor out of it, like that found in their receptacula chyli?
Goddard's queries may be summed up as raising doubts about the ‘sweetly acidic’ quality attributed to the fluid present in the lymphatic and chyliferous vessels by Kohlhans. If observed in a fasting animal (when the ventricle was empty), the acidity could be explained by analogy with familiar processes, and required no recourse to a hypothetical universal solvent. The quantity in which it was present in a baby would differ greatly from that in the adult animal. It would be subject, moreover, to diminution and replenishment. But in that case it was subject to generation and growth, and hence also to corruption, thus undermining the claim that it differed radically from other bodily humours in its nature and its operations within the animal body. Goddard also suggested further experiments for investigating the manner in which such a liquor worked in animal bodies.
How Kohlhans answered Goddard's queries in the paper that the minutes record as having been read by Oldenburg to the Royal Society during the last of its discussions of the ‘animal alkahest’, and whether it left any traces on the scientific thought of the later seventeenth century, remain issues for future research to explore and clarify.
Value of archival work in digital times
In this concluding section we give a brief account of the problems we encountered in finding the papers associated with the early Royal Society meetings on the ‘animal alkahest’ and in identifying the author of the paper that initiated the discussions. We discuss why they could not be solved simply by consulting the digitized archives.
As briefly noted earlier, rediscovery of the three documents mentioned here was the result of research we conducted at the Royal Society with very specific goals. Nevertheless, the number and complexity of these archives made this search particularly difficult, requiring great patience and perseverance to overcome several formidable obstacles.
To begin with, as a result of successive classifications and reclassifications by succeeding cataloguers, each of the three documents had been filed in a different ‘Classified Papers’ volume. With the increasing specialization of knowledge developed in later centuries,46 the first document—‘Experimentum quod ostendere videtur, Liquorem quondam, Alkahesto Analogum, in Animalibus reperiri’—was consigned to volume 14, devoted to works on ‘Physick’ or medicine (Cl.P/14i/2, f. 1r–v). In keeping with MS 703,47 which lists the papers read at Royal Society meetings from 1660 to 1738, the document whose English title is ‘Of a liquor from animals like the Alkahest’ (f. 4v–5r) ought to have been filed in volume 12, corresponding to ‘Anatomy/Surgery’. The corresponding entry in the card catalogue is also in English, but the title is slightly different from the entry in MS 703. As a result the identification of this document as the one read by Oldenburg at the session on 16 October became far more difficult.
Moreover, the name of Oldenburg on the original document had been crossed out in a differently coloured ink and after much effort it became possible to read the name as ‘Dn Colhans’ although the card catalogue mentions a ‘Dr Cothary’ and the index of Classified Papers 14i a ‘Dr Catharys’ as Oldenburg's source for the Latin text. The name could not be traced in the medical literature of that time, and initially led the research into a dead end. However, this document and the copy addressed to Boyle mentioned above48 are the only ones retrieved when searching for ‘alkahest’ in the digital catalogue.
On the basis of biographical sources such as D. Bierens de Haan, Colhans came to be identified usually as Johann Christoph Kohlhans (1604–77), a Hebraist, astronomer and mathematics professor at Coburg, but without any prominent involvement in medicine. Indeed, when de Haan began in 1888 to edit the inaugural volumes of the Huygens correspondence, he included the letter (March 1662) by Oldenburg mentioning our Tobias Ludwig Kohlhans (here spelt with ‘C’) but identified him erroneously as J. C. Kohlhans.49 The English editors of Oldenburg's correspondence translated and reproduced this letter together with de Haan's annotation. As the latter referred to J. C. Kohlhans, the editors, too, spelt the name of Oldenburg's visitor with a ‘K’ and retained the misidentification.50
The error is understandable. Few letters survive from this period of Oldenburg's life, and, when retrieved from the printed correspondence of the recipients, they have already been annotated by editors.51 J. C. Kohlhans, moreover, was a prominent scholar in his time. His writings were sufficiently well known in several parts of Europe to bring him to the attention of nineteenth-century and twentieth-century editors.52 Oldenburg himself was probably well acquainted with the astronomer's work, because J. C. Kohlhans's Tractatus Opticus (his name spelt once more with an initial ‘K’) appears in a list of books sent to him by John Collins.53
Many other members of the international network of the Royal Society's future secretary, too, seem to have been aware of this difference in spelling.54 For example, Peter Serrarius informed him in a letter dated July 1667 (which Oldenburg probably never received) that he had already dispatched ‘your Packet from Dr Colhans’ through a messenger.55 In other words, the difference in spelling between both quasi-homonyms was neither whimsical nor due to the workings of chance, but was a choice made intentionally by Oldenburg, which proved crucial for our rediscovery.
Finally, after much further research, Albrecht von Haller's anatomical bibliography, listing a letter on animal spirits, and referring to the lymphatic fluid, led us to identify the paper's author as Tobias Ludwig Kohlhans.56
As regards the second document—‘Qaieries [Queries] upon ye Exp[e]rim[en]t to prove a Liquor in analogie to ye Alkahest, to be found in the bodies of Animalls’—it omits the name of its author. Careful comparison of the handwriting together with hints found in Birch's work and MS 703 allowed us to attribute it safely to Goddard. It is filed in volume 12 of ‘Classified Papers’ (‘Anatomy/Surgery’, CI.P/12i/1, f. 1r–v). Although this agrees with MS 703, which lists a paper entitled ‘Enquiries concerning the Alkahest’ (f. 4v–5r), the card catalogue files it under ‘Chemistry’, without mentioning its author's name and with the title ‘Is a liquor analogous to alkahest to be found in animal bodies’, differing from the former two titles. Finally, in the digital catalogue it is listed as ‘Queries on the experiments to prove a liquid’, where, among other variations, the term ‘alkahest’ is not mentioned at all and ‘liquor’ is replaced by ‘liquid’. Moreover the name of Goddard is still missing.
The third and last document—‘The liquor Alchahest or ye Im[m]ortal Dissolvent of ye Philosop[hers]’—contains the recipe of alkahest itself (CI.P/11i/8, f. 1r–v). It is not mentioned in MS 703 (possibly because it was not read at the meeting) and is filed in volume 11, devoted to papers on ‘Pharmacy and Chemistry’. In this case, the document is, indeed, where one would expect to find it, and, moreover, placed next to other memoirs by Goddard. Similarly, in the card catalogue it is anonymously filed under ‘Chemistry’.
However, when searching the digital catalogue and checking different spellings of the word ‘alkahest’ (since only two entries correspond to this spelling, as mentioned above), the variant ‘alchahest’, which was the one actually used in the title, produced no results. In fact, mistyping—which is not uncommon in digital catalogues—transformed the document title into ‘Alchahert’ or ‘immortal dissolvent’. Therefore, the only remaining hints making it possible to locate it in the card catalogue were its being mentioned in the meeting records and its actual presence among the ‘Classified Papers’.
Although all three documents were eventually ‘found’, this was not the product of chance. To restore once again the original structure of a series demanded not only a sound working hypothesis but also great persistence in following it up. That points to the conclusion that a direct careful search in the archives is unlikely to be supplanted by digital media, at least in the near future.57
We thank Floriano Jonas Cesar PhD and Silvia Waisse Priven MD PhD for invaluable help and support at all stages of the preparation of the paper; Mr Keith Moore, Head Librarian, and his staff for fully supporting our archival researches at the Royal Society and providing photographic images of the rediscovered manuscripts; and Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for research support.
Authors are listed in alphabetical order.
↵1 From ‘Journal Book of the Royal Society’, reprinted in T. Birch, The History of the Royal Society of London (A. Millar, London, 1756), vol. 1, pp. 49–53.
↵2 Classified Papers 14i/2; 12i/1 and 11i/8 respectively; complete references are presented in the last section of the paper.
↵3 R. K. Bluhm, ‘Henry Oldenburg, F.R.S. (c. 1615–1677)’, Notes Rec. R. Soc. 15, 183–197 (1960); M. Boas Hall, Henry Oldenburg: shaping the Royal Society (Oxford University Press, 2002); The correspondence of Henry Oldenburg (ed. and trans. A. Rupert Hall and M. Boas Hall) [hereafter Oldenburg correspondence], vol. 1, ‘Preface’, pp. xix–xxiv (University of Wisconsin Press, Madison, WI, 1965).
↵4 W. S. C. Copeman, ‘Dr Jonathan Goddard, F.R.S. (1617–1675)’, Notes Rec. R. Soc. 15, 69–77 (1960), at p. 72; J. M. Rampelt, ‘The last word: John Wallis on the origin of the Royal Society’, Hist. Sci. 46, 177–201 (2008).
↵5 Cited in Copeman, op. cit. (note 4), p. 73; derived from Anthony à Wood, Athenae Oxonienses, 2nd edn (Printed for R. Knaplock, D. Midwinter and J. Tonson, London, 1721), vol. 2, p. 538. For Goddard's contributions, as recorded in Royal Society Minutes, see the entry for Goddard, compiled from Birch's History, in G. E. Scala, ‘An Index of Proper Names in Thomas Birch, ‘The History of the Royal Society’ (London, 1756–1757)’, Notes Rec. R. Soc. 28, 263–329 (1974), at p. 268.
↵6 ‘Concerning an animal alkahest, queried in Catharys, Med. Germ., 2pp, in Latin’, Classified Papers 14i, ‘Physick’, index, Royal Society Archive.
↵7 First suggested by Dr Floriano Cesar; on the difficulties of identifying Kohlhans see the concluding section of the paper.
↵8 Volker Wappmann, Durchbruch zur Toleranz. Die Religionspolitik des Pfalzgrafen Christian August von Sulzbach 1622–1708 (Degener, Neustadt a. d. Aisch, 1998); A. Coudert, The Impact of the Kabbalah in the seventeenth century: the life and thought of Francis Mercury Van Helmont (1614–1698) (Brill, Leiden, 1999), p. 35.
↵9 G. Toepke (ed.), Die Matrikel der Universität Heidelberg von 1554 bis 1662 (Carl Winter's Universitätsbuchhandlung, Heidelberg, 1886), part 2, p. 318. It records the matriculation of 'Tobias Ludoicus Kolhans, Gothâ-Thuringus (med. Stud.)’ on 8 November 1653 and, in an editorial footnote, his being made a doctor of medicine on 1 February 1655.
↵10 Tobias Ludovicus Kolhans, Dissertatio inauguralis de liene cui appendicis loco annectitur vasorum lymphaticorum nuper inventorum observatio (Aegidius Walterus, Heidelberg, 1654). It was in the Appendix to it, on the newly discovered lymphatic vessels, that Kohlhans first mentioned the ‘animal alkahest’.
↵11 Kohlhans referred to Horne as ‘Promotoris & Fautoris mei’ in §57 of his inaugural dissertation. Horne had obtained his medical degree in Padua before extending his peregrinatio medica to Naples, Basel, Orléans, Montpellier and England, partly with Thomas Bartholin, also a Leiden student (1637–40). Returning to Leiden, he was appointed professor of anatomy and surgery after the death of Otto Hernius in 1652. His foremost interest remained anatomy, and in 1652 he was among the first to describe the ductus chyliferus (thoracic duct) in human bodies. Albrecht Von Haller, Bibliotheca anatomica (Orell, Gessner, Fuessli et Socc., Tiguri, 1774), vol. 1, p. 474; see also G. A. Lindeboom, ‘Johannes Van Horne (Hornius)’, in Dictionary of scientific biography (editor-in-chief C. C. Gillispie), vol. 6, pp. 508–509 (Charles Scribner's Sons, New York, 1970–90).
↵12 Boas Hall, op. cit. (note 3), pp. 34–38; Oldenburg (with Boyle's nephew) was in Frankfurt in May 1658 during the ‘election of the next Holy Roman Emperor’, and there met Francis Mercurius van Helmont.
↵13 Letter from Oldenburg to Huygens, 29 March 1662, in Oldenburg correspondence, vol. 1, pp. 445–448, esp. p. 446; misidentified in index p. 494, and in note 1 on p. 447 as J. C. Kohlhans.
↵14 Boas Hall, op. cit. (note 3), p. 57.
↵15 Oldenburg correspondence, vol. 1, p. 447.
↵16 Letter from Oldenburg to Boyle, October 1661, Oldenburg Correspondence, vol. 1, pp. 440–442; also published in The correspondence of Robert Boyle (ed. M. C. W. Hunter, A. Clericuzio and L. Principe), vol. 1, pp. 466–469 (Pickering & Chatto, London, 2001) [hereafter Boyle correspondence]; p. 468 notes that this document must have been attached to a letter dated 29 September 1664; a translation of this document appears in Boyle correspondence. This copy of the paper had slight modifications, as, for instance, in the title; whereas the paper delivered at the Royal Society was entitled ‘Experimentum quod ostendere videtur, Liquorem quondam Alkahesto analogum in Animalibus reperiri’ (Classified Papers, 14i/2, ‘Physick’, Royal Society Archive), the document attached to the letter to Boyle lacked the preface and bore the title ‘Liquorem quondam, Alkahesto analogum, in animalibus reperiri’. A reply by Boyle has not yet been located.
↵17 Boyle correspondence, vol. 1, p. 466.
↵18 The Sceptical Chymist or Chymico-Physical Doubts and Paradoxes, Touching the Spagyrist's Principles Commonly called Hypostatical (F. Cadwell for F. Crooke, London, 1661), p. 216 (two editions in 1661 published by F. Crooke). See also L. M. Principe, The aspiring adept, Robert Boyle and his alchemical quest (Princeton University Press, 1998); A. Clericuzio, ‘Boyle & the English Helmontians’, in Alchemy revisited (ed. Z. R. W. M. Martels), pp. 192–199 (E. J. Brill, Leyden, 1990).
↵19 Hermann Boerhaave, Elements of Chemistry (J. Pemberton; J. Clarke; A. Millar; and J. Gray, London, 1735), vol. 1, p. 489; he devoted a full section (pp. 489–500) of the chapter on ‘menstruums’ to a thorough discussion of the alkahest; Elementa chemiae (Ioannis Rudolphi Imhof, Leiden, 1732), p. 849; section on the alkahest, pp. 848–868. See also A. M. Alfonso-Goldfarb, M. H. M. Ferraz and S. Waisse, ‘Chemical remedies in the 18th century: mercury and Alkahest’, Circumscribere 7, 19–30 (2009).
↵20 W. Pagel, Paracelsus: an introduction to philosophical medicine in the era of the Renaissance, 2nd edn. (S. Karger, Basel, 1982), pp. 142, 201 and 366; B. Joly, ‘L'alkahest, dissolvant universel, ou quand la théorie rend pensable une pratique impossible’, Rev. Hist. Sci. 49, 305–344 (1996), at p. 314; P. A. Porto, ‘“Summus atque felicissimus salium”: the medical relevance of the Liquor Alkahest’, Bull. Hist. Med. 76, 1–29 (2002), at p. 3.
↵21 G. H. Turnbull, ‘Some Correspondence of John Winthrop, Jr., and Samuel Hartlib’, Proc. Mass. Hist. Soc. (3) 72, 36–67 (1960), at pp. 44–46; see also ‘Copy letter in scribal hand[?], Hartlib to John Winthrop the Younger’, in Hartlib papers, 2nd edn, ff. 7/7/1A–8B (HROnline, Sheffield, 2002), at ff. 7/7/3B–4B.
↵22 R. G. Frank Jr, Harvey and the Oxford physiologists: a study of scientific ideas (University of California Press, Berkeley, 1980); O. Temkin, Galenism. Rise and decline of a medical philosophy (Cornell University Press, Ithaca, NY, 1974), ch. 4, pp. 134–192; Thomas Fuchs, The mechanization of the heart: Harvey and Descartes (trans. M. G. Grene) (University of Rochester Press, 2001).
↵23 Frank, op. cit. (note 22), esp. ch. 4, pp. 90–114; Audrey B. Davis, Circulation physiology and medical chemistry in England 1650–1680 (Coronado Press, Lawrence, KS, 1973), ch. 2, pp. 12–30.
↵24 Kolhans, op. cit. (note 10); T. L. Kolhans, Litterae de spiritu animali ad J. D. Horstium … olim privatim scriptæ, nunc … divulgatæ (1658). William Harvey expressed his sceptical views on the implications of the lacteal and lymphatic discoveries in letters to the same J. D. Horst, municipal physician of Hesse-Darmstadt, on 1 February 1655 (n.s.) and 13 July 1656, R. Willis (Eng. tr.), The works of William Harvey, M.D. (Sydenham Society, London, 1847), pp. 612–615; Horst's numerous published works included a Physica Hippocratea, Tackenii, Helmontii, Cartesii, Espagnet, Boylei, &c … (F. Knoch, Francofurti, 1682).
↵25 M. Boylan, ‘The digestive and “circulatory” systems in Aristotle's biology’, J. Hist. Biol. 15, 89–118 (1982), on the spleen at pp. 106–107; Andreas Laurentius, Historia anatomica humani corporis et singularium eius partis multis controversiis & observationibus novis illustrata (1599; cited from J. Mettayer, Paris, 1600), Lib. VI, ‘Controversiae anatomicae, de lienis vsu contra Galeni caluminatores’, pp. 321–325; W. Pagel, The smiling spleen (Karger, Basel, 1984); A. Wear, ‘The spleen in Renaissance medicine’, Med. Hist. 21, 43–46 (1977); C. Webster, ‘The Helmontian George Thomson and William Harvey: the revival and application of splenectomy to physiological research’, Med. Hist. 15, 154–167 (1971).
↵26 Thomas Bartholinus, Vasa lymphatica nuper hafniae in animalibus inventa et hepatis exsequiae (Mathurini Du Puis, Paris, 1653); Cap. VIII of Anatomia reformata (Adriani Vlacq, The Hague, 1660, 1663, 1665), esp. the 1665 edition for the appended Epistles from Johannes Waleus; also W. Pagel, New light on William Harvey (Karger, Basel, 1967), Appendix 1 on Waleus, pp. 113–134.
↵27 W. Pagel, Joan Baptista van Helmont: reformer of science and medicine (Cambridge University Press, 1982), pp. 129–140; Ioanne Baptiste van Helmont, Ortus medicinae, id est initia physicae inaudita (Ludovicum Elzevirium, Amsterdam, 1652), ‘Ius Duuviratus’, pp. 239–250.
↵28 Pagel, op. cit. (note 27), pp. 187–195; A. G. Debus, The French Paracelsians: the chemical challenge to the medical and scientific tradition in early modern France (Cambridge University Press, 1991), p. 118.
↵29 Kohlhans, op. cit. (note 10), §37, p. 7; commendation of Helmont in introduction [A2] after mentioning blood circulation, and §30. Hoghelande was mentioned in Kohlhans, op. cit. (note 10), §38, pp. 7–8, and in §61 on p. 12. Cornelis van Hoghelande (1590–1676) was a close friend of Descartes and wrote Cogitationes … Nec non, brevis historia oeconomiae corporis animals, atque mechanice explicator (Ludovicum Elzevirium, Amsterdam, 1646) on Cartesian lines, but see also note 32 below.
↵30 Kolhans, op. cit. (note 10), §38, p. 7.
↵31 ‘… vn certain vent très subtil, ou plutost: vne flame très viue & très pure, qu'on nomme les Esprits animaux.’ ‘Traité de l'Homme’, Oeuvres de Descartes (ed. Charles Adam and Paul Tannery) (Léopold Cerf, Paris, 1909), p. 129.
↵32 On Hoghelande, note 29; for Descartes’ candid comparison of Hoghelande with his ‘infidel’ disciple Regius, see his letter to Princess Elisabeth, March 1647, in Descartes, Correspondance (ed. C. Adam and G. Milhaud), vol. 7, pp. 274–276 (Presse Universitaires de France, Paris, 1960), at p. 276. On de Raes, Kohlhans, op. cit. (note 24), p. 18; also E. G. Ruestow, Physics at seventeenth and eighteenth century Leiden: philosophy and the new science in the university (Nijhoff, The Hague, 1973), ch. 16 on de Raey; Theo Verbeek, Descartes and the Dutch: early reactions to the Cartesian philosophy, 1637–1650 (Southern Illinois University Press, Carbondale, IL, 1992); Coudert, op. cit. (note 8), pp. 35, 45, 265 and 274. On Leibniz, see, for example, a reference to ‘Monsieur Kohlhas’ in a ca. 1680 letter in C. von Rommel, Leibniz u. Landgraf Ernst von Hessen-Rheinfels … (J. Rütten, Frankfurt am Main, 1847), vol. 1, pp. 275–276.
↵33 To develop a clearer exposition, the description and comments on the documents follow a different sequence from that of the Minutes.
↵34 ‘The liquor Alchahest or ye Im[m]ortal Dissolvent of ye Philosop[hers]’, Classified Papers, 11i/8, ‘Pharmacy and Chemistry’, Royal Society Archive, fl. 1r. The various descriptive phrases used for the alkahest in this document were drawn from Helmont's treatise Ortus medicinae, id est initia physicae inaudita and are traced to that source in the ‘Index Verborum’ appended by Otto Tachenius to the 2nd edition (Juntas & Joannem Jacobum Hertz, Venice, 1651); and by Boerhaave on the etymology of the alkahest, in Elements of chemistry, op. cit. (note 19), pp. 490–492; Elementa chemiae, op. cit. (note 19), vol. 1, pp. 850–854.
↵35 2 Maccabees (Apocrypha), chapter 1, verses 19–20 in King James version; that text was cited for ‘aqua crassa’ in van Helmont's Ortus Medicinae (1652 Elzevir edition), ‘Elementalivm Figmentvm’, preceding a description of Helmont's famous willow-tree experiment, p. 88.
↵36 ‘The liquor Alchahest’, op. cit. (note 34), fl. 1r.
↵37 Its power to dissolve the salts in all other bodies is referred to in the same manuscript; ibid., fl. 1v.
↵38 See P. A. Porto, Van Helmont e o conceito de gás: química e medicina no século XVII (Edusp – Educ, São Paulo, 1995); and ‘Os primeiros desenvolvimentos do conceito helmontiano de gás—parte II’, Quím. Nova 26, 141–146 (2003).
↵39 The expression ‘Diana's doves’ is found in a wide range of authors from Nicolas Flamel to Jean d'Espagnet, and also in the alchemical manuscripts of Isaac Newton. See [J. d'Espagnet], Arcanum hermeticae philosophiae opus (Paris, 1623), pp. 32–33; W. R. Newman, The lives of George Starkey, an American alchemist in the Scientific Revolution (University of Chicago Press, 1994), pp. 131–132; B. J. T. Dobbs, The foundations of Newton's alchemy: or, ‘The hunting of the greene lyon’ (Cambridge University Press, 1975), esp. pp. 167 and 176–177.
↵40 Pagel, op. cit. (note 27), pp. 46–49; W. Pagel and P. Rattansi, ‘Vesalius and Paracelsus’, Med. Hist. 8, 309–328 (1964), reprinted in Walter Pagel, From Paracelsus to Van Helmont (ed. M. Winder) (Variorum Reprints, London, 1986), esp. pp. 310–314.
↵41 Pagel, op. cit. (note 20), pp. 54–64 and 198–200.
↵42 Pagel, op. cit. (note 27), pp. 19–34.
↵43 Ibid., pp. 59–60 and 88.
↵44 Ibid., p. 208.
↵45 ‘Qaieries [Queries] upon ye Exp[e]rim[en]t to prove a Liquor in analogie to ye Alkahest, to be found in the bodies of Animalls’, Classified Papers, 12i/1, ‘Anatomy/Surgery’, Royal Society Archives.
↵46 The arrangement followed represented a simplification of the system adopted by Philosophical Transactions, abridged by John Lowthorp and completed by T. Birch in the middle of the eighteenth century. Keith Moore (with additions by M. Sampson), A guide to the archives and manuscripts of the Royal Society (The Royal Society, London, 1995), pp. 20–21.
↵47 ‘Index of papers read before the Royal Society 1660–1716’, Royal Society Archives.
↵48 Letter from Oldenburg to Boyle, op. cit. (note 16).
↵49 D. Bierens de Haan (ed.), Oeuvres complètes de Christiaan Huygens, pubiées par la Société hollandaise des sciences, vols 1–4 (M. Nijhoff, La Haye, 1888–1950); see G. Sarton, review of the publication in Isis 21 (2), 213–215 (1934).
↵50 Huygens, letter 1003, Oeuvres complètes de Christiaan Huygens, vol. 4, op. cit. (note 49), p. 108; see also I. Kalter, curator, Kometen und hebraïsche Punkten: Johann Christoph Kohlhans (1604–1677). Ausstellungskatalog. Coburg: Landesbibliothek Coburg, August 26th—October 12th, 2004, <http://www.landesbibliothek-coburg.de/kohlhans.htm>.
↵51 Boas Hall, op. cit. (note 3), pp. 65–66.
↵52 Kalter, op. cit. (note 50).
↵53 Letter from J. Collins to Oldenburg, December 1668, in Oldenburg Correspondence, vol. 5, pp. 211–214.
↵54 All references to Tobias Ludwig began with a capital ‘C’, whereas those to Johann Christoph invariably spelt his surname with a capital ‘K’.
↵55 Letter from Peter Serrarius to Oldenburg, 5 July 1667, in Oldenburg Correspondence, vol. 3, pp. 446–447.
↵56 Von Haller, op. cit. (note 11), vol. 1, p. 474.
↵57 Although CESIMA has developed a digital repository of documents, including the full collection of the microfilmed manuscripts of the Royal Society, the richness and consequent complexity of its archives made direct inspection mandatory and led eventually to the discovery of these documents.
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