by Lisa Jardine
In Paris, Sir Constantijn did not keep his scientist son’s doubts about Micrographia to himself. Among the French virtuosi who seized eagerly upon Micrographia was Adrien Auzout, a talented observational astronomer and instrument-maker whose name is associated with the development of the eyepiece micrometer for long telescopes. As soon as he heard about Hooke’s book, he arranged to borrow Sir Contantijn’s copy.9 Shortly after Huygens senior had returned to Holland, Auzout wrote from Paris to Christiaan Huygens in The Hague: ‘A few days ago I received a letter from Monsieur de Zulichem [Sir Constantijn], who told me that you, like myself, had found a quantity of interesting things in Hooke’s book.’10
Auzout’s interest in Micrographia and its author began a chain of events which had a lasting effect on Hooke’s long-term reputation, largely without his own intervention or even participation. It is important to note that right at the start, Auzout had been shown Christiaan’s less than generous letter to his father about Micrographia, expressing reservations about some of Hooke’s findings and claims.
Among the ‘quantity of interesting things’ which had caught Auzout’s attention in Micrographia were those parts of the text dealing with Hooke’s technological innovations in microscope manufacture, rather than the extraordinarily minute details of natural phenomena seen under the microscope and reproduced in the plates. A description of a machine for grinding accurate lenses, interpolated into the preface, particularly intrigued Auzout, since he was already involved in a critique of a similar machine advertised by Giuseppe Campani in Italy, and was himself proposing one to the circle of astronomers lobbying for the setting up of the new Royal Observatory in Paris.11
In the course of some passing remarks on telescopes in the preface to Micrographia, Hooke had been drawn into an aside on the need for readily available, high-quality lenses. The way of meeting this need, he went on, was to invent a ‘ready way’ (a machine) for making telescope object glasses. And he announced that he was in the process of refining such an ‘engine’, ‘by means of which, any Glasses, of what length soever, may be speedily made’.12
In an elaboration of these remarks, marked off from the main body of the text by its distinctive typography, Hooke sets down the technical details of his machine, illustrating his remarks with an engraving on the first plate of the volume alongside the well-known images of Reeves’s microscope and scotoscope.13
Auzout was a man on the make, eager to make a splash scientifically – in fact, he was trying hard to get himself made a member of the new French Académie des sciences (he succeeded in 1666, although he resigned from it in 1668). He read the preface to Micrographia in February 1665, and hurriedly inserted a critical response to it into a letter he had composed the previous year on the subject of the Italian Campani’s improved telescopes which he was preparing for publication.14 The expanded version of his ‘Letter to the Abbé Charles’ appeared in print in Paris in April or May 1665, and Auzout immediately sent a copy of the pamphlet to Oldenburg, with whom he was already in correspondence concerning Campani’s observations of the 1664 comet.15 Oldenburg produced a summary in English, including the criticisms of Hooke at length, and passed it to Hooke. Hooke responded with a letter to Oldenburg rebutting all Auzout’s criticisms, and this letter – preceded by Oldenburg’s English summary of Auzout’s published letter – was published in the Philosophical Transactions of the Royal Society of 5 June 1665 as ‘Mr Hooke’s Answer to Monsieur Auzout’s Considerations, in a Letter to the Publisher of these Transactions’.16
So now Hooke had a scientific ‘quarrel’ of a rather fashionable kind on his hands (intellectual quarrels in print were all the rage in London and Paris). The accusation which most exercised him at this stage was that he had not conducted proper trials of his lens-grinding machine, and that to have published an account of such an untried instrument, thereby claiming its priority, was unworthy of the Royal Society, given the Society’s commitment to experimental accuracy. As official Curator of Experiments, and having been admitted as a full Fellow of the Society only a year previously, Hooke was extremely anxious to clarify his position. He was quick to point out that there was a clear disclaimer placed prominently at the beginning of Micrographia, entirely dissociating the Royal Society from any ‘Conjectures and Quaeries’ of his own. Perhaps, he suggested, Auzout’s English had not been good enough to follow the text.17
As it turned out, Hooke’s suspicion was entirely correct. Auzout responded in a letter to Oldenburg of 22 June. He admitted that his English was indeed poor, and that, besides, he had only had Micrographia in his possession for two days. Inevitably he had not read it all, particularly since the illustrations were so captivating, and drew his attention away from the text.18
On 1 July Auzout wrote again, expressing the hope that this letter was with Oldenburg, and announcing his eager anticipation of meeting Wren, who was expected in Paris at any moment.19
Auzout’s public accusation of premature publication was unjust. There is firm evidence that Hooke had conducted proper trials of his machine and was continuing to do so. On 3 November 1664 Oldenburg told Boyle: ‘Mr Hooke is now making his new instrument for grinding Glasses, the successe whereof you will shortly heare of.’20 By the end of November Moray was giving detailed descriptions of Hooke’s machine and the trials being conducted with it to Christiaan Huygens. On 30 January 1665 (just before he dispatched Huygens’s copy of Micrographia) Moray told him that Hooke was being prevented from conducting further trials on his lens-grinding machine by his duties as Curator of Experiments to the Royal Society:21 ‘Mr Hooke has had so many matters on his plate these past days that he has not been able to carry through to completion his new invention for the lenses for telescopes.’22
By September Huygens was reporting to Auzout that there were problems with the operation of the ‘iron circle’ Hooke proposed using.23Again Moray admitted to Huygens that the demands the Royal Society was making on Hooke’s time were hampering his ability to complete projects undertaken:
We keep Mr Hooke so fully occupied with a thousand little things that he has not yet given me the description he promised me of his machine for measuring the refraction of light in water [a machine undertaken at the same time as the lens-grinding machine, and also announced and illustrated in Micrographia]. As soon as he does so I will forward it to you.24
The repeated claims that Hooke’s machine had never been tested were, as Hooke always insisted, entirely without foundation.
In fact, Auzout knew far more about Hooke’s lens-grinding machine than he was letting on in his letters to Oldenburg, even before the publication of Micrographia. Throughout the latter half of 1664 he had been receiving copies, at least in part, of the letters being exchanged about it between Huygens and Moray. The Anglo–Dutch connection had once again prepared the way, just as it had done in the case of the pendulum clocks. A vigorous correspondence in French between Moray and Huygens, who sometimes wrote to one another several times a week, ensured that whatever Hooke was doing in London, Huygens knew all about it within days. And whereas Moray was a scientific amateur, who enjoyed participating in events at the Royal Society but had little expertise in any specialism, Huygens was well able to pick up, adopt and adapt experimental details passed to him by Moray.
Huygens and Moray had begun corresponding about lens-making machines in summer 1664.25 Huygens reported to Moray Campani’s claim to have ‘a new way of making lenses using a lathe or turning device, and without using any kind of a mould’. Moray responded with the news that Hooke had shown such a machine to the Royal Society ‘five or six months earlier’, although it had yet to be demonstrated in action.26 Two months later he gave Huygens a much fuller account of the lens-grinding machine, presumably because by November he had had sight of the diagram and description given in Micrographia (licensed by the Society that month):
I think I told you earlier that a few months ago Mr Hooke proposed a sort of lathe for making the lenses for telescopes without using any
form or mould. His invention is, to place the lens on the end of a rod which turns on two pivots, then to have a circle of iron attached to the end of another rod which turns in the same fashion, in such a way that the edge of the circle covers the centre of the lens, then applying pressure with the circle upon the lens so that the two rods make whatever angle is desired; according to how big or small the angle between the rods is, the surface of the lens has the section of a large or small sphere.27
In December Moray enlarged on this description in response to a further enquiry from Huygens. By now Hooke had built a prototype, which he had shown to the Royal Society:
Mr. Hooke’s machine is set up and I will keep you informed as to the success of this invention, and of all the details of its structure, if it warrants the effort of describing it to you. Concerning moulds or forms, he claims not to use any. But if it turns out to be necessary to use moulds to give initial shape, and then to polish them, as you suggest, on [an iron] circle, be assured that I will keep you informed. But it looks as if the circles will shape the lenses much more quickly than moulds could do, and so moulds are unnecessary, and as you told me, Campani does not use them at all.28
Huygens copied at least one of these letters to Auzout, keeping him up to date with the information Moray was supplying, in connection with Auzout’s interest in Campani’s machine.29 He also made a note to himself that the use of the iron circle was an exceptionally good idea, and one that he would consider incorporating into an equivalent machine himself, which in typical Huygens fashion he subsequently did.30 At the end of December he devoted a whole letter to Auzout to ‘explaining the iron circle for working lenses’.31 A minute for another letter to Auzout, written on 15 January 1665, shows that they were still discussing refinements to the circle.32 From his further correspondence with Moray it is clear that by now Huygens had built his own prototype machine, and was experimenting with Hooke’s ‘iron circle’.33
Here, as in the case of the balance-spring watch, we have Christiaan Huygens – eager for recognition in the new Paris Académie – absorbing technical detail gathered from informants in London, and incorporating it in his own scientific instruments without acknowledgement. This is precisely the period during which Hooke later accused Oldenburg and Moray of having leaked details of his balance-spring watch to Huygens, and Huygens of having adapted his own prototype watches accordingly.
Hooke was entirely unaware of this correspondence. He knew nothing of the swift transmission to Holland (and thence to Paris) of material he was presenting to the Royal Society in his official capacity as its recently appointed Curator of Experiments.34 In Moray’s eagerness to be seen by Huygens to be fully au fait with new scientific developments in England, he freely communicated construction details of Hooke’s lens-grinding machine, which an expert instrument-designer like Huygens could readily seize upon and adapt. So Moray was transmitting troubling levels of detail concerning a patentable machine, in whose development there was already significant European competition, to his friend Huygens, who in turn discussed technical details with Auzout.
Meanwhile, Oldenburg replied to Auzout’s letter of 22 June 1665 on 23 July, detailing Hooke’s further rebuttals of Auzout’s continuing refusal to accept the practicality of the lens-grinding machine. In view of Auzout’s lack of knowledge of English, and Hooke’s of French, Oldenburg offered himself as epistolary intermediary: ‘If you wish, I will be the go-between, since you do not know enough English to write to him nor he enough French to reply.’35
But all was not as it seemed. For by 15 July Hooke and the other curators had been instructed to move out of London, to Epsom, in the company of John Wilkins and William Petty, to continue Royal Society experiments safely away from risk of the plague.36 Even if Oldenburg had shown Hooke Auzout’s second letter before he left, there is nothing to suggest that Hooke either drafted notes to it or wrote a full answer.37
Emergency measures were in place restricting the post during the plague epidemic. The most secure route for getting letters to Hooke was apparently via Wilkins. In September Moray told Oldenburg that he intended ‘to write within a day or two to Dr Wilkins, to put Mr Hook to the finishing his observations &c concerning the Cometes’.38 Two days later Moray advised Oldenburg: ‘I think you will do well to let Mr Hook know what [Huygens] sayes of Glasses [lenses] & what else concernes him by writing to Dr Wilkins.’39
At the end of September Hooke went to the Isle of Wight to attend to family business (his mother had died at the beginning of the summer), taking him even farther out of range of regular correspondence with Oldenburg in London. He remained there till the end of the year, occupying himself with geological investigations on and under the cliffs of Freshwater Bay. He returned briefly to London at the end of December, before once more returning to Epsom, finally rejoining the Royal Society circle in London in late February 1666.40
From July 1665 onwards, then, it appears that Hooke is being ventriloquised by Oldenburg in his absence in the Auzout–Hooke ‘controversy’.
On 13 August Auzout wrote once again to Oldenburg, again responding to Hooke point by point. Oldenburg’s translation of this letter into English survives. It is apparently intended for Hooke’s use, since it carries marginal annotations goading Hooke to respond to supposed ‘slights’ by Auzout in the text (which Oldenburg has made rather more provocative than the original): ‘What say you to this?’; ‘A handsome sting again will be necessary’; ‘Me thinks, here you may toss railleries with him’; ‘To this I say, He will needs make you say, what you say not’; ‘Non sequitur. You must rally with him again.’41 Perhaps Oldenburg hoped to have Hooke respond to Auzout himself when he returned to London. Perhaps he intended to act once more as intermediary, and to write another letter to Auzout, incorporating remarks of Hooke’s provoked by his own deliberately antagonistic annotations and prompts. Neither thing happened, because Auzout now acted pre-emptively. In July or August 1665 he republished his original ‘Letter to the Abbé Charles’, together with the entire correspondence to date between himself and Hooke (via Oldenburg) in French in Paris.
Oldenburg reacted indignantly, claiming he had never intended his last letter for publication. Auzout replied in some puzzlement – surely the correspondence had always been intended as part of a public epistolary controversy:
I am very upset that you are not happy that I have, at the request of my friends, published the letter that you were gracious enough to write to me to explain Mr Hooke’s feelings [concerning my continuing criticisms]. I did not consider this letter to be something belonging entirely to you, but rather as the reply of Mr Hooke, and because we had already both of us begun to print material on that topic, I saw no harm in supplying the rest, since our friends wanted so much to have sight of the continuation of the dispute.42
It seems clear from Oldenburg’s discomfiture that he had indeed himself composed the detailed arguments attributed to Hooke in the letter to Auzout of 23 July. He now found himself embarrassed by their being made public, which risked bringing the fact to Hooke’s attention. Fortunately, as we know, Hooke’s French was limited. In what was probably an act of damage limitation, Oldenburg summarised the arguments of Auzout’s new book in English, abbreviating and omitting parts Hooke might have construed as betrayals of trust, and published his synopsis in Philosophical Transactions.
Meanwhile Moray, Huygens and Auzout were corresponding vigorously about the affair, savouring every contentious sentence in the exchanges, often passing each other’s letters on as enclosures, and including copies of the Journal des sçavans and Philosophical Transactions where appropriate. In early June 1665, Auzout told Huygens that he was eagerly awaiting the arrival of Philosophical Transactions, which he gathered would contain the first instalment of his exchanges with Hooke:
I am told from England that Mr Hooke has taken up my objections against his machine in the first book of Philosophical Transactions which I hope will arrive on Sunday. We shall see what he says.
I had almost forgot to desire you to send to Mr Hugens either the whole former Transaction [June issue], or so much of it as containes Hooks answer to Auzout & withall to let him know what Hook is doing as to his glasses [lenses and telescopes]. I have told him I would give you that task. L. Brounker will let you have hugens’s letter.43
The exchanges amongst this group shaped received opinion concerning the possibility of machine manufacture of precision lenses, and has continued to be treated as the authoritative account of the episode by historians of science ever since.44 Yet, although Hooke played a starring role in these exchanges, this was an extended conversation in which he had no direct voice, and over which he could exercise no control.
And although Hooke’s close friend Christopher Wren was in Paris throughout this period, in daily contact with the Auzout circle, he apparently did nothing to clarify the nature of Hooke’s machine, nor did he communicate the fact that Hooke was now absent from Royal Society circles. Wren was certainly consulted over the Auzout/Hooke affair. In April 1666 Auzout reported to Oldenburg that he had spoken to Wren shortly before he returned to England, concerning Hooke’s proposed method for increasing the focal length of lenses by filling the space between two lenses with liquid (a topic associated with the lens-grinding machine debate).45
By the end of July the Royal Society members had almost all dispersed because of the plague. Hooke, Wilkins and Petty were at Epsom, together with a substantial amount of experimental equipment, and assistant operators. Boyle was briefly with them, then retired to Oxford. Moray was with the King, first at Hampton Court, then at Oxford. For much of the period we are looking at Brouncker was on a ship off Greenwich seeing to navy business. Oldenburg stayed in London with his family, in a state of considerable agitation about the possibility of his succumbing to the plague (he made a will carefully separating his personal affairs from those of the Royal Society). During this time the Royal Society had two locations: a correspondence address with Oldenburg in London; and a transferred ‘real’ centre of operations in Oxford, where Moray and Boyle had established weekly meetings of a caucus of members.46 Huygens was in The Hague throughout, corresponding with Oldenburg, Moray and Auzout (his father, however, was in Paris for three months in early 1665).47
