Telescopium: sive Ars perficiendi novum illud Galilaei visorium instrumentum ad sydera in tres partes divisa.

Frankfurt: Paul Jacobi for Luca Jennis, 1618.

First edition, extremely rare, of “the first book about the telescope, its invention and use” (Zinner). Written by the Milanese scholar Girolamo Sirtori in 1612, only four years after the telescope was invented, it contained a complete set of instructions and diagrams for building a refracting telescope, and gave in the second part the first detailed account of Galileo’s telescope. Dedicated to the Grand Duke Cosimo II de’ Medici, Telescopium is also one of the most important sources for the history of the invention and first uses of the telescope. Sirtori records the arrival of a telescope in Milan in May 1609, brought by ‘a Frenchman’ who was an associate of its inventor, Hans Lipperhey, and presented to the Count of Fuentes; this was about a month before Galileo first learned of the invention (according to Siderius Nuncius). Sirtori claims to have seen and handled Lipperhey’s very first telescope, but also suggests that the device was known to others before the Dutchman. He also provides an account of a famous meeting organised by Federico Cesi, founder of the Accademia dei Lincei, dated by Rosen to 14 April 1611, at which a select group of natural philosophers and mathematicians, including Sirtori himself, met Galileo and experienced the performance of his telescope in person – this was “the public unveiling of the term telescope” (Rosen, p. 31). Galileo received a copy of Sirtori’s work in 1633 from the hands of Cassiano dal Pozzo, his fellow Lincean and great collector and begetter of the ‘Museo Cartaceo’ (Cassiano Dal Pozzo to Galileo [in Rome], Rome, 18 June 1633, Opere XV, p. 158); this is presumably the copy which belonged to François Arago, cited by both Brunet and Riccardi, and having notes in Galileo’s hand. ABPC/RBH list only three other complete copies, two of them in Macclesfield sammelbands, the other an ex-library copy with removed stamps. The Honeyman copy, a presentation copy from the author to Tommaso Mingoni (Menghin), Leibartzt of Rudolph II, and a friend of Kepler, lacked one of the plates. OCLC lists Chicago and Yale only in North America; VD17 gives only 5 locations.

“Almost immediately after its invention, the telescope evolved from a mere optical toy into a ‘scientific instrument,’ an instrument of a new type which at the time was called ‘philosophical’: the manipulation of such instruments allowed scholars to attain natural philosophical truth. In this way, the telescope paved the way for other scientific instruments which also emerged in the course of the seventeenth century, such as the air pump, the barometer, and the microscope. The emergence of the telescope was an important episode in the history of science and technology not only because it marks the invention of a new device, or because it changed man’s image of the universe, but also because it helped change the ways in which natural philosophy was practiced and what counted as ‘science’ …

“The search for the inventor of the telescope has a long tradition which began almost immediately after the invention of the instrument. In Telescopium, the earliest book on the telescope, published in 1618, but composed in 1612, Girolamo Sirtori already doubts whether Lipperhey, the first demonstrator of the instrument, was also the inventor of the device” (Van Helden, Origins, p. 2). Indeed, Sirtori writes (pp. 24-26, translation from Van Helden, Invention, pp. 50-51):

‘In the year 1609 [sic, for 1608] there appeared a genius or some other man, as yet unknown, of the race of Hollanders, who, in Middelburg in Zeeland, visited Johannes Lippersein [i.e., Lipperhey], a man distinguished from others by his remarkable appearance, and a spectacle maker. There was no other [spectacle-maker] in that city, and he ordered many lenses to be made, concave as well as convex. On the agreed day he returned, eager for the finished work, and as soon as he had them before him, raising two of them up, namely a concave and a convex one, he put the one and the other before his eye and slowly moved them to and fro, either to test the gathering point or the workmanship, and after that he left, having paid the maker. The artisan, by no means devoid of ingenuity, and curious about the novelty began to do the same and to imitate the customer, and quickly his wit suggested that these lenses should be joined together in a tube. And as soon as he had completed one, he rushed to the court of Prince Maurits and showed him the invention. The prince had one [or, had been acquainted with one] before, and lest it should be suspected that [the device] was of military value, and very necessary, had kept it a secret. But now that he found by chance that it had become known he disguised [his prior knowledge], rewarding the industry and good intentions of the artisan. Thence the novelty of so great a thing was spread through the whole world, and many other telescopes were made. But none of those turned out better or more apt than the first one (which I have seen and handled).’

Sirtori goes on to describe his first encounter with a telescope.

‘In the month of May [1609] a Frenchman rushed into Milan and offered such a telescope to the Count of Fuentes. He said that he was an associate of the inventor from Holland. When the Count had given it to a silversmith to put it in a silver tube, it came into my hands. I handled it and examined it, and made similar ones, in which I observed that many inconveniences occurred because of the glass. I therefore went to Venice in order to obtain a supply [of lenses] from the artisans there and, being still unskilled in the art, I delivered a finished lens to someone so that he could make similar ones. I squandered some money uselessly and lost the lens, having learned nothing more than that the business is to be perfected by chance and by the laborious selection of lenses. As it happened when I acquired one, I imprudently ascended the tower of St. Mark, in order to try it out at a distance. Someone, having decried the novelty from the square, pointed it out to others, and a throng of noble youths, filled with curiosity, rushed upstairs and almost overwhelmed me – although they were well-behaved – and having courteously asked for the telescope, they began to look through it, passing it from one to the other. Tired by this delay of almost two hours, and by the unexpected occurrence, at length each one was summoned home by his empty stomach, and so the crowd began to grow thinner and I began to breathe again. The next day, remembering the perils of the previous day, and fearing that the same would happen if they were to find out my lodgings, concerning which they were inquiring as they departed, I left.’

Sirtori now describes his efforts to understand the origins and method of construction of the telescope.

‘Yet, I was annoyed by this one thing, that I still was uncertain about that art, and had to acquire it with so much effort, and I thought of how I might master it. Meanwhile the rumor increased, and many lies went around (which whetted the appetite) about how it was asserted in the letters of merchants that in the Netherlands and Spain telescopes of this sort were to be found by which a man could be recognized at three miles. I took a trip to Spain, in the belief that all exceptional things would be obtainable there more surely and more quickly. When I came to Gerona [it Catalonia], someone found out that I had the kind of glass that everyone was talking about. Soon, a certain curious architect appeared, asking whether he could see my telescope. Repelled by the man’s aggressiveness, I began to refuse; he began to urge me anew, and would not go away, so that I came to suspect that the man was actually dedicated to the art. Nor was I wrong, for when he had looked at a remote tree as long as he wished, he further asked me to permit him to examine, take out, and handle the glasses. I agreed, knowing that because of his age he was unequal to the task, should he seek to imitate it. After he had handled and diligently considered the glasses, he led me to his lodgings and, having locked the door, he revealed the tools of the art, completely eaten away by rust. At one time he had been a spectacle-maker, and the entire art was buried there. As I felt myself won over by the favour of the expert in the art, I gave myself entirely into his friendship, and poured out my secret to him quite freely. He, moreover, showed me the outlines of the art, described in a book, and upon my asking, permitted me to copy out the proportions by means of only three points. After that it was not difficult for me to figure out the entire [series], and then, having examined the matter diligently, improved it by labor in daily experiments and expenses, and confirmed it, to perfect it and reduce it into this table, which I disclose to you. Our architect, as I learned later, was a brother of Roget of Burgundy, who at one time lived near Barcelona, a man of great diligence, who first introduced and established the art in Spain. He begot three sons, one of them, dedicated to letters and religion, devoted himself to the order of St. Dominic, and this monk wrote down the art. Nowhere was this art more exact than among those Roget brothers.’

A 1959 research paper by Simon de Guilleuma claimed that evidence he had uncovered suggested that this was the French born spectacle maker, Juan Roget (c.1550 – c.1617-24). However, Van Helden (Origins, p. 6) disputes the claim that Roget was the true inventor of the telescope: “the work of the sixteenth-century Juan Roget is important, not so much because we would be allowed to attribute the invention of the telescope to him, but because Roget’s work tells us more about the circulation of the know-how of lens-making from which the telescope originated.”

Sirtori continues:

‘Already I seemed to have learned the art whose outlines only I possessed. But things had turned out so nicely according to my wishes, that I hoped shortly to be able to perfect a telescope, and so, hastening to the royal court on private business, and quickly freed from there, I returned to my homeland, where I saw to the construction of some tools, and having hired some workers, began to observe how they practiced their art and to train my hand little by little. After long work and effort, when I made a trial of the lenses, it was especially evident to me that, from the same form, almost all lenses had turned out unequal to each other. When I diligently examined the cause of this, I found that it was mainly due to the inequality of the form, but also to the varied thickness of the glass, and lastly also to the unsteadiness of the hand.

‘With my hopes and efforts still frustrated, I went to Rome, where I had learned an abundance of all arts flourished and, moreover, many distinguished and celebrated men were dedicated to this study. Nothing more fortunate could have happened to me. For Galileo was there with his unforgettable telescope. By chance, on a certain day, Prince Federigo Cesi, Marquis of Monticello, a learned man and benefactor of the sciences, had invited him to dinner in the vineyard which is called Malvasia, and besides him some other learned men. Before sunset, when they arrived there, they began to look through the telescope at the inscription of Pope Sixtus V above the Lateran portal, which was about a mile distant. I took my turn and looked and read the inscription to my satisfaction. Later that night, after dinner, we observed Jupiter and the motion of his companion stars, after which, sufficiently invigorated by the sight of such brilliance and by the curiosity of the matter, they withdrew in order to examine the telescope. And Galileo himself, in order to satisfy their curiosity, took out the lens and the concave glass, and showed them openly. In the meantime, I examined and measured the tube, and then also handled and inspected the lens, so that I can with confidence, from skilled experience, report what kind of thing it is. The exact proportion of the lens and the concave [glass] was the only thing to prevent me from possessing the whole art.’

Acquiring the final details of the proportions of the lenses necessitated further travels:

‘In the year 1611, when I had made a journey to Germany, and had come to Innsbruck, where His Serene Highness Maximilian, Archduke of Austria, resides, leaving my lodgings, I chanced to meet a servant of his who inquired where I was from and where I was going, and I revealed my intentions to him. After greetings and other gestures of courtesy, he left. In the evening when I sat down at the dinner table, a servant appeared with a note advising me not to neglect to greet the prince, and at the appointed hour in the morning he led me to him, at whose sight I abased myself in the usual way, and kissed his hand. After some introductory remarks, he presented an opportunity for a longer conversation. After other [topics], there was a discussion about Galileo’s telescope concerning which I told him the truth, and I made mention of its design. He took me to a porch where there was a board on which Galileo’s design was described and drawn, the design which Galileo himself had sent to Maximilian of Bavaria, the Archbishop and Elector of Cologne. And the Elector himself had sent it to His Serene Highness the Archduke by means of Johannes Zuckmesser, a mathematician and his chamberlain. When I had studied it attentively, I turned to the prince and said that I possessed exactly the same thing, but had brought it from Spain. And having produced my paper patterns, I superimposed the outline of the first difference of the convex [lens], which according to the Rogets is the shape of the first lens (in Italian of common vision [i.e., a convex lens used for the correction of presbyopia]), and it was a section of the same circle. With my eye I had also measured the outline of the little globe at the convex lens, and not waiting for the word of the prince, I also produced the paper pattern which is the seventh and last of the concave lens according to the same Rogets, and laid it on [the board], and it was found to be exactly the same.

‘As the prince saw that I had the same proportions which the Elector of Cologne had sent him, he asked how this instrument could be made. ‘I could do it, Most Serene Prince,’ I replied, ‘provided that I had iron forms according to these proportions.’ Craftsmen and interpreters were provided, with orders that they were ready to be instructed. Among the many in that region, hardly one was to be found who understood what was to be made, or how. In the meantime, a violent plague made it advisable for me to move on, and so, having said goodbye to the prince, I was carried downstream to Vienna, where I gave myself wholly to the purpose of making the forms, sparing no labor or expense. I know that princes and great men could not attain what I, by some chance or fate, attained in Spain.’

Most historians now tend to regard as futile the search for the true inventor of the telescope. “What happened in 1608 was in fact not an invention at all, but merely a recognition of the great potential of a device, which must have been around for some decades, as a kind of toy or as a device whose purpose was to correct or improve vision. Indications of the awareness of the magnifying power of a combination of two lenses, long before the year 1608, are indeed abundant in the contemporary literature. For instance, in 1538 the Italian scholar Girolamo Fracastoro (c. 1478-1553) wrote: ‘If someone looks through two eye-glasses, of which one is placed above the other, he shall see everything larger and more closely.’ Or to quote Albert Van Helden in 1977: ‘The telescope was not invented ex nihilo’” (Zuidervaart, p. 10). In 1977, Van Helden [Invention, p. 25] concluded that the question ‘who invented the telescope’ actually boils down to the question: ‘who first realized that such a device could be used for another purpose and set about adapting and improving it in order to obtain the greatest magnification possible?’ That question, Van Helden remarked, could not be answered on the basis of the available evidence. He concluded: ‘When all is said and done, we are still left with the fact that the earliest undeniable mention of a telescope is to be found in the letter of 25 September 1608, which Lipperhey carried to The Hague and that Lipperhey was the first to request a patent on the telescope. But to award the honour of the invention to Lipperhey solely on that basis is an exercise in historical positivism.’

Sirtori devotes a substantial portion of Telescopium to the method of construction of a refracting telescope, such as was used by Galileo, and in particular the techniques for grinding and polishing the two lenses which constitute the instrument. “The lenses needed in a Galilean telescope are the objective and the eye-lens; the former was almost invariably a plano-convex lens, and the latter plano-concave. While the eye-lens could be made with the processes in use in the craft of spectacle-making, the objective required the development of new implements. In the case of spectacles the portion of the lens that is used when looking at a particular object is quite small, approximately the size of the eye’s pupil; the lens quality requirement then only extends over such an area at any one time. The eye-lens in a telescope works in a similar way. In the case of the objective, however, the entire lens is used all the time, no matter what particular object in the field of view the observer examines; the quality requirement then extends over the entire lens diameter. In practice, the convex surface ought to be entirely regular, and exactly spherical. In addition, to obtain a focal length of a metre or more, as in most telescopes of the time, the radius of curvature must be longer than those of contemporary spectacle lenses. New tools had to be made and new production techniques devised. Basically, the glass blank in the form of a plate had to undergo the preliminary step, during which the lens was roughly shaped, the grinding step, where the surfaces were made spherical, and the polishing step, where the surfaces were finely lapped to remove the residual micro-roughness. Each step needed specific tools and techniques, which only in small part could be borrowed from the craft of spectacle makers, and were mostly developed by the artisans on their own. As a final step, the lens was tested for optical performance, and then accepted or discarded.

“Once carefully selected for the absence of visible defects, the glass plate had first to be rounded. To this purpose, a circle was marked with a divider [illustration, p. 71], probably with a cutting diamond attached to the turning arm … Next, the lens surfaces had to be given a preliminary shaping. This required on one side the securing of the lens to a holder, and on the other side a tool plate with some curvature (opposite to that to be generated) to abrade against. As to the holder, [illustration, p. 47] shows the drawing of a handle used by spectacle-lens makers. The glass plate was attached with pitch, bitumen or similar adhesives to the top disc of the handle; the use of plaster is also reported. As to the tool plate used at this stage, it was generally made of metal (iron, typically, but also copper or other materials) …

“Grinding is the key operation performed in optical workshops that gives the lens surfaces a spherical shape. The tools are similar to those used for preliminary shaping, although the process is more refined. Metal tool plates might have been used at first. Sirtori reports a technique to generate the mild concavity of the plate by means of a curved file [illustration, p. 35]. However, it was observed that this method was quite crude, each stroke removing the plate material along a line and the end results, in terms of surface regularity, were poor. Also, the use of moulds to examine the actual profile, reported by Sirtori, appears to be difficult to put into practice, considering the mould’s shallowness in cases of long radii of curvature …

“The grinding process was accomplished with the so-called spoltiglia. According to Sirtori, this was a fine abrasive produced from emery, dissolved in a bowl of water and allowed to precipitate partly. The liquid was then transferred to a new bowl, water was added again, and the largest particles in the liquid were allowed to deposit on the bottom. The process was repeated three or more times, so that only the smallest emery particles remained. In the process described by Torricelli, the abrasive was added when needed, until the entire surface was uniformly ground. Then, no more abrasive was added, continuing the grinding with the remaining spoltiglia, only adding a little drop of water, or just breathing on the surfaces if they were drying up. The operation was only terminated when the powder had become white, very fine and greasy ‘like butter’. Carefully carried out, such a process produced very finely ground surfaces, of excellent spherical shape and already almost capable of forming an image” (Molesini, pp. 272-6).

Sirtori wrote Telescopium in 1612, and it was advertised in the catalogue of the Frankfurt book fair held that spring (Rosen, p. 41). However, it remained unpublished until 1618, and Sirtori was scooped for the honour of being the first to use the term ‘telescope’ in print by Giulio Cesare Lagalla, another attendee at Cesi’s banquet, who published De phoenomenis in orbe lunae novi telescopii usu A D. Gallileo Gallileo nunc iterum suscitatis physica disputatio at Venice in 1612.

Brunet V, 403; Carli and Favaro 75; Honeyman 2854; Macclesfield 838 & 839 (both sammelbands); Riccardi I(ii) 461; Sotheran, Second Supplement 3843 (“An important work in connexion with the early history of the telescope, containing also full instructions how to make and use it”); Zinner, Bibl. 4681 & Instr. 536; not in Cinti or Houzeau & Lancaster. Freedberg, The Eye of the Lynx, 2002. Molesini, ‘Testing telescope optics of seventeenth-century Italy,’ pp. 271-280 in: The Origins of the Telescope (Van Helden et al, eds.), 2010. Zuidervaart, ‘The ‘true inventor’ of the telescope. A survey of 400 years of debate,’ pp. 9-44 in ibid. Rosen, The Naming of the Telescope, 1947. Van Helden, ‘The invention of the telescope,’ Transactions of the American Philosophical Society 67 (1977), pp. 1-67. On Sirtori himself, about whom little is known with certainty, see: Rössler, ‘Hieronymus Sirturus,’ in Zeitschrift für ophthalmologische Optik mit Einschluss der Instrumentenkunde 24 (1936), pp. 1-17. 



4to (195 x 150 mm), pp. [2], 3-75, 78-81, [1, blank], with two folding woodcut plates at pp. 18 and 81 (complete). Woodcut device on title, woodcut diagrams in text (three full-page). Old limp vellum.

Item #4706

Price: $55,000.00