Unrecognized Classical Transmissions

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Unrecognized Classical Transmissions

The portolans may not be the only unrecognized transmission from classical times.

Leonardo da Vinci

Leonardo da Vinci (1452 - 1519) intensively used books as inspiration or blueprint for his technical drawings. That is not well-known[1] and sometimes simply neglected. In the prominent publication of Reti (1974) the steam canon "Architronito" is presented (not by Reti) as an invention of Leonardo. But Leonardo wrote that it was an invention of Archimedes. The same numbers for projectile weight and range that Leonardo presented was found by Reti (1962) in a book by Robertus Valturius, "De Re Militari" (1472).[2]

Either Leonardo had it from him or he and Valturius had the same classical source we no longer know. The 15th century was the high time of search for classical texts. Some survived in only a single edition. It is very likely that the 15th century had some classical texts that are no longer extant.[3]

According to statistics about Leonardo's extant writings, some 6000 pages,[4] Augusto Marinoni (1974)[5] could calculate by two ways a loss of 50 and 75 %. So probably more than half of Lenoardo's writings are lost.

According to historic records[6] his Codex Trivulzianus had

  1. originally with Leonardo: 192 folios
  2. (before 1608) with Pompeo Leoni: 55 folios
  3. (before 1637) with Count Arconati: 54 folios
  4. today in Bibliotheca Ambrosiana of Milan: 51 folios

So the main loss happened in the 16th century. As the Madrid codices show, this loss was probably not random but systematic.[7]

With that in mind, one should expect serious gaps in his extant writings and technical sketches. Especially the latter could be removed from the bulk as valuable economic or military secrets. It is therefore no valid argument to dismiss the following as odds by chance. It may be rather the peak of a historical issue waiting for excavation. In hindsight it seems unfortunate that the facsimile editions in the 1970s were published in less than 1000 copies. A broader public might have found more still unrecognized inventions.

The Antarctica Globe

The c. 1514 globe gores of Leonardo with the first correctly positioned and sized Antarctica and one of the first with "America". Royal Collections of Windsor Castle, London.
His c. 1514 globe gores with Antarctica are a striking link to the other traces of a classical portolan world map. It is the first Antarctica with the correct size in the correct place. For the others see here. The globe has some features in common with other contemporaries probably originating with Vespucci. There is a "probable personal connection between the two distinguished Florentines, Leonardo da Vinci and Amerigo Vespucci through various existing correspondence."[8]

There is a claim that in 1757 a Mr. Ximenes found a letter from Leonardo to Christopher Columbus. It dated to 1473 and was about the probability to reach India on the "intended" way.[9] The date 1473 seems too early but would have some important implications about Leonardo and possibly Columbus too.

Leonardo's Bicycle

See Leonardo's Bicycle

The Gyroscopic Compass

A water powered compass drawn by Leonardo da Vinci. The main features suggest the depiction of a gyroscopic compass. He may have been inspired or may have copied it from an unknown source. Windsor Castle, Royal Library, London.
In 1974 there was a press conference for the presentation of the Codex Atlanticus and Codex Madrid editions. The German news magazin "Der Spiegel"[10] wrote that Leonardo's sketches included a gyroscopic compass like the one built by the US Sperry Gyroscope Company in the 1920s. But in Reti (1974) - the book about the editions - no such drawing was mentioned.
Gyroscope study by Leonardo da Vinci
I could not find out on what sketch of Leonardo this news was based on. "Der Spiegel" did not print it and some present historians never heard of it. I found a strange compass in a recent facsimile publication.[11]

It has a clearly visible compass indicator and was powered by a water wheel. The water wheel was not the overshot preferred on land but an undershot possible to install on a ship. Something that could resemble a cardanic mounted gyroscope is visible in the center under the compass. But the drawing focused on the wheels for power transmission to the central section.

The whole device only makes technical sense as a gyro compass because anything else would not need the power. But the crucial part of the power transmission to the spinning gyro is not visible. On early gyroscopes it was done using a strong airflow. The base below the gyro could be a wind bag. The whole device would be a simple direction indicator like the ones used on small aircraft today, not a north finding compass as used on larger ships.

The gyro itself is sketched rather simply. Cardanic mounts were known around 1500 and Leonardo had a sketch with one.[12] This drawing may need another one with the mount details of the gyroscope. It is probably lost. Whether Leonardo already understood the principle of a gyro compass seems not certain. The drawing may be inspired or copied from an unknown source.

Towards the Vacuum

On folio 58v (Madrid I ?) Leonardo wrote that the air becomes rarer with altitude and has less resistance.[13] That implies a lower air pressure with altitude and a vacuum beyond earth. It was not the knowledge of his time and a sensation when Pascal experimentally proved it in 1648.

The Parabolic Trajectory

The emergence of cannons after 1250 raised the interest in the shape of a projectile's path, called the ballistic trajectory. It was crucial for targeting. Since Albert of Saxony (c. 1320-1390) the trajectory was thought to be of three parts. First a straight line, then a circular arc because of gravitation, and than again a straight line to the bottom.[14]

The parabola as ballistic trajectory by Leonardo was centuries ahead of his time.
According to Bern Dibner,[15] that view lasted in military books until the later 17th century. It was asserted by the mathematician Nicolo Tartaglia in 1537 and lasted by the scientists until Galileo around 1600 suggested a parabola and Newton in 1687 calculated it.

But Leonardo, in Codex Madrid I, folio 147r, suggested a parabola in c. 1493. It was against all knowledge and experience for a century before and after him. No one else had suggested it then. Galileo derived it from experimental analyses mathematically. There is no evidence that Leonardo did it that way or even had the knowledge to do it.

It is suggested[16] that he got it by observation. Could Leonardo really be such a better observer than generations of bowmen and gunners before and after him? Due to air resistance a real ballistic trajectory is not a parabola. Depending on the projectile material it may be closer to what the military books suggested then.

The simplest explanation is a classical book on mechanics that Leonardo had but that we no longer know. The parabola is a Greek term from classical times and we have transmitted texts about it. It is not far fetched they had used the parabola for describing the ballistic trajectory. The rarer air with altitude may be from the very same source.

Cornelis Drebbel

Cornelis Jacobszoon Drebbel (1572-1633) from Alkmaar, Netherlands, was a well known inventor then. He is credited with the invention of mercury fulminate, scarlet dye, the air cooler, the thermostat, the thermometer, the microscope with two convex lenses and the navigable submarine. If only partly true he was still one of the most important inventors of his time. But two of his inventions seem beyond his time.[17]

The Submarine Air

The second submarine of Cornelis Drebbel at a trial run c. 1624 in Thames river, London. Contemporary lithography by G. W. Tweedale. Note the sub has neither a tower nor a snorkel.
His largest submarine could stay submerged for 3 hours with 16 passengers and 6 oar men. That was achieved by a chemical it carried in large flasks. In his book Drebbel wrote that heated saltpetre (potassium nitrate) changed the "nature of air".

In 1662 the famous scientist Robert Boyle wrote in his diary about a conversation with "an excellent mathematician", who was still alive and had been on the submarine. He reported Drebbel's opinion that only a part of the air was necessary for breathing. After that quintessence part was consumed the "flame of live in the heart will go out". Drebbel was able to get this quintessence for life by a "chymical liquor" he had stored in bottles in the submarine.

Other reports indicate Drebbel was heating nitre that generated oxygen.[18] But it generated potassium oxide or hydroxide too. That is able to remove carbon dioxide from the air. So he made a crude rebreather nearly 300 years earlier. But the air had to flow through the bottles by some pump.

Some points of this story seem beyond Drebbel's abilities. He correctly stated that only a part of the air (today called oxygen) supports life and can be replaced. But that was against the science of his time which offered a simpler explanation.[19]

His correct explanation could only be created by experiments and logical deduction. But there is no record Drebbel ever did that. Had he, he would be praised as a high scientist-founder like Galileo and not just an inventor. It seems he had knowledge that did not originate with him and he did not know how it was created.

For his submarine not the oxygen generation was crucial but the removal of carbon dioxide by the rebreather. Again Drebbel had no explanation how it worked and was probably not aware of it. The rebreather was more difficult to develop than an oxygen generator. Because as an experimental indicator it needed the use of humans, not just a candle.

There is no direct way to build a rebreather by chance. Unlike an oxygen generator that releases a gas, one has to pump the air through the rebreather to scrub the carbon dioxide. He indicated no knowledge that he had to remove some gas. So how could that machine have happened by chance? It seems more likely he got both concepts from an unknown source he never mentioned.

The Barometric Clock

The barometric clock of Cornelis Drebbel patented in 1598 and then known as "perpetuum mobile". Print by Hiesserle von Choda (1557-1665).
The most astonishing invention of Drebbel was a clock driven by the daily changes of the barometric pressure. The clock did not have an hour plate but a tidal indicator and was called by Drebbel his "perpetuum mobile". He received a patent on it in 1598 and got very famous just from the clock.

That it really worked is attested in a 1615 letter by Johannes Kepler (1571-1630). Drebbel was with his clock at the court of Emperor Rudolf II in Prague where Kepler was then the chief mathematician. Kepler was the leading physicist of his time and wrote about Drebbel's perpetuum mobile: "it is good, it convinced me, it finds my approval".

But neither Kepler, nor Drebbel nor anyone else had an explanation how it worked. The barometric pressure was unknown then until Torricelli measured it in a secret experiment in 1643 using a mercury tube. And the discovery of the daily variation still had to wait an additional 20 years for a better barometer.

It is strange to imagine that Drebbel and Kepler had an operational pressure measurement device in use without realizing it. The pressure oscillations are invisibly small on a sealed clock body. It had to have an ingenious lever mechanism to record it. It took until 1770 for the London watchmaker James Cox to build a barometric clock again.

Any discovery of this clock by chance seems highly unlikely. If Drebbel really invented it, he had to have a barometer. Only from an accurate barometer it was possible to deduce and design the clock.


In all three cases - the oxygen theory, the rebreather and the barometric clock - Drebbel had knowledge that could only be achieved with considerable experimental effort and quantitative analysis. The clock even needed a barometer before. There is no evidence or hints that he conducted the necessary experiments or was even aware of them. Instead he had no knowledge of air pressure and did not know that his rebreather removed a gas.

At his time there is no other source known that could have provided the necessary knowledge. The most recent epoch with the ability to do that was in classical times. By developing window glass and concrete they had proven skills for an experimental quantitative approach.[20]

Main source: Clausing, Achim: "Cornelis Drebbel: Ein vergessener Pionier der Moderne", Spektrum der Wissenschaft Juli 2011, pp. 88-95

Traces of the Telescope

It is common opinion that the first telescope was invented around 1606 in the Netherlands and nobody had anything like it before. Robert Temple did an extensive investigation on this subject and found a lot of evidence to the contrary.[21] Dozens of lenses in museums from archaeological digs support his view.

The Pharos Telescope

The earliest telescope mentioned in texts belong to the Pharos lighthouse tower of Alexandria at the time of Ptolemy III Euergetes (c. 280-221 BC). It could see ships far away[22] and was first mentioned by Giovanni Battista della Porta in his famous book "Magia Naturalis" 1558. According to Temple, Porta then goes on to describe the construction of a telescope, many years before Galileo.[23] In 1763, Bonaventure Abat[24] offered further sources, one possibly Arabic. He concludes that the mentioned object was a mirror, not a lens.[25] This was supported by Count Guillaume Libri in 1835[26] with several Arabic sources.[27]

In recent times the opinion came up that the Pharos was not built to guide ships in the harbor and had no fire atop. The fire to guide ships was from a later time after the Mediterranean Sea was more secure. This opinion together with the telescope accounts suggests the Pharos was an early warning station against raider fleets. It could allow sufficient warning time to allow Alexandrian forces to await the raiders in their most vulnerable stage - at the water line. That would explain well why such an expensive, monumental building was created at all. Lighthouses were then and today always smaller.

Caesar's Telescope

Temple found a lot more references to ancient telescopes. But one stood out in a way that may connect classical, medieval and early modern references. It was by the early scientist Roger Bacon (c. 1214-1292). He wrote in his 1267 Opus Majus:

"For in this way Julius Caesar, when he wished to subdue England, is said to have erected very large mirrors, in order that he might see in advance from the shore of Gaul the arrangement of the cities and camps of England."[28]

How credible is it that Caesar in 54 BC had a telescope? It is true that a mirror set is able to work as a telescope. It may even be superior to a lens telescope of the 17th or 18th century.[29] Because of color distortions, lens telescopes could not rival good mirror systems for a long time. But the latter were clumsy and needed to be polished often to keep a bright image at night.

For a stationary daylight observation, a mirror system was a better choice but rarely used. The mirrors would not be "very large" to get good magnification but needed an exact curvature and alignment. About 100 mm diameter would be enough.[30] A role for larger mirrors seems doubtful.[31]

Still in the 16th century Bacon's words were ridiculed because mirrors could not enlarge the view.[32] Today we know better. But Bacon could not know it, he had to have received it from an ancient source. The passage with Caesar is not in our transmitted texts. So Bacon had access to another version we no longer have.[33]

Roger Bacon's Telescope

It seems Bacon was in possession of a text that described how a lens telescope could be built. The 1911 Encyclopædia Britannica wrote about the passage in his Opus Majus: "He certainly describes a method of constructing a [lens] telescope, but not so as to lead one to conclude that he was in possession of that instrument."

According to the Encyclopædia Britannica "about 1257, Bonaventura, general of his order, interdicted his lectures at Oxford, and commanded him to place himself under the superintendence of the body at Paris. Here for ten years he remained under supervision, suffering great privations and strictly prohibited from writing anything for publication."

That was circumvented by an order of pope Clement IV. (1265- 1268) for whom he wrote 1267 the Opus Majus and an unknown number of other books. In 1278 his books were condemned by Jerome de Ascoli, general of the Franciscans, later to become Pope Nicholas IV., and he was thrown into prison for fourteen years. He died soon afterwards. The oldest known reference to the imprisonment of Bacon is from around 1375. It says the order was given by the head of the Franciscans because of unspecified "suspected novelties".[34]

In his Opus Majus, Bacon was the first scientist who described the use of lenses and optics. He only had to put two different lenses together to get a telescope or a microscope.

In 1551 - well before the official invention of the telescope - the English polymath Robert Recorde wrote in his book "The Path-way to Knowledg, Containing the First Principles of Geometric" about Friar Bacon:

"Greate talke there is of a glasse that he made in Oxforde, in whiche men myght see thynges that were doon in other places and that was judged to be done by the power of evyll spirites."

According to Recorde, Bacon was then accused of being a black magician. But Recorde thought it may only have been applied mathematics, geometry.[35]

Due to the availability of lenses then it seems almost certain that Bacon built a telescope and made observations like Galileo did 330 years later. The mountains on the Moon and the moons of Jupiter are visible even with the crudest telescope. Neither was in agreement with the then prevailing theology and an improvement of the instrument would have made the conflict even worse.

Bacon mentioned a classical book about secret inventions written in Greek. Bacon's extant writings are said to contain information about steam machines, self-moving wagons, diving equipment, flying machines and gunpowder.


With three writers (Leonardo, Drebbel, Bacon) knowledge was identified that could not originate from their time. Bacon mentioned an event in 54 BC that is unknown otherwise and he mentioned a secret book that could be the way of transmission.

The machines Bacon mentioned had some cross match with those of Leonardo. Leonardo was with the most powerful people of Italy and therefore well-connected. We don't know his sources but it could well include the very same book Bacon mentioned.

The first globe gores with Antarctica were drawn by Leonardo and are a striking link to the other traces of a classical portolan world map. So Leonardo had more classical material than Bacon and probably from different sources - not just one book. But no copy of a classical source text survived to present times by way of any of the three writers.

Given the availability of lenses since the 13th century it seems certain that some people between 1300 and 1600 built simple telescopes. But no direct report about it or their astronomical observations survived. Because of the expected large public impact - as Galileo had in 1609 - this is a strong indicator for a systematic and organized suppression.

Like Bacon was called a black magician, others may have faced that accusation, too. The Secret Courts were tasked to find any person suspected of black magic. The accused were never heard and the only way of punishment was to kill them.[36] The silence until Galileo suggests this organization was still active after their last record of 1490.

I thank Bibhistor for suggesting this page and crucial contributions.


  1. Jump up In his writing about Leonardo's scripts, Augusto Marinoni mentioned that most historians are unaware of this because Leonardo often did not note his sources. See: Reti, Ladislao (ed.): The Unknown Leonardo, 3 volumes. New York, 1974
  2. Jump up It is very unlikely that Leonardo ever built such a gun. See: Simms, D. L.: "Archimedes' Weapons of War and Leonardo", The British Journal for the History of Science, Vol. 21, No. 2 (Jun., 1988), pp. 195-210. Reti, Ladislao: "Il mistero dell'Architronito." in: Raccolta Viniciana 1962, 19, pp. 171-184
  3. Jump up I was told there is an Italian book with a list of those classical texts which survived only as a single edition found in the 14th or 15th century. Most texts had further bottleneck transmissions (single texts) in the 5th and 9th century. Some single manuscripts got lost after their first print edition.
  4. Jump up In "Der Spiegel" (1967) 5000 were claimed before the new find of 700 in Madrid. So the number of 6000 pages floating around on the internet seems credible. But these are only 3000 folio sheets.
  5. Jump up In his chapter about Leonardo's writings in Reti (1974)
  6. Jump up Mentioned by Marioni in his chapter about Leonardos writings in Reti (1974)
  7. Jump up We don't know the content of the 16 torn out pages. But it must be of value that someone did it to these beautiful books. Given the damage he did he was probably not just a fan of the master.
  8. Jump up This citation and other very useful information about the globe is found in an anonymous article here
  9. Jump up Grothe, Hermann: Leonardo da Vinic, Berlin (1874), p. 20
  10. Jump up No. 42/1974 (14.10.1974)
  11. Jump up Zöllner, Frank: Leonardo da Vinci: 2 Volumes, 2012, Vol II, p. 499. Given location: Windsor Castle, Royal Library, RL 122821
  12. Jump up Should be on Codex Madrid I, folio 13v.
  13. Jump up "...die Luft, die sich mit zunehmender Höhe verdünnt und weniger Widerstand leistet." From the German Edition of Reti (1974), "Leonardo - Künstler, Forscher. Magier", (1996), p. 180
  14. Jump up It is explained in his Wikipedia entry
  15. Jump up In Ladislao Reti (ed.): The Unknown Leonardo, New York, 1974.
  16. Jump up By Bern Dibner (1974) for example.
  17. Jump up It was not the submarine, it really happened. A semi-submersible (like some recent writers suggested) instead of a submarine seems unlikely. It would be more difficult and risky to build. The low speed of his sub made the necessary depth keeping for a snorkel very difficult. It would hinder any semi-submersible operation or made the sub obviously bogus. The depth keeping problem may be the reason why his submarine only operated in the Thames river. It probably sometimes touched the ground and would soon get lost in deep waters.
  18. Jump up It is unlikely that he heated it inside the submarine. A fire there would create highly toxic carbon monoxide and kill the crew.
  19. Jump up According to the then prevailing Aristotle, fire was an element in the objects and air could only hamper the release of it. Air itself was an element too.
  20. Jump up The German scientist Prof. Dr.-Ing. Heinz-Otto Lamprecht reported that the Roman concrete had the same grain-size distribution curves like our modern concrete. That is only possible to achieve using systematic experimental quantitative analysis. Lamprecht, Heinz-Otto: Opus Caementitium - Bautechnik der Römer, Beton-Verlag, Düsseldorf, 1985.
  21. Jump up Temple, Robert: "The Crystal Sun, Rediscovering a Lost Technology of the Ancient World", London (2000)
  22. Jump up Something from 400 km or more is mentioned. That is a typical exaggeration we find in all early telescope accounts. But sometimes it was possible to lock beyond the curvature of Earth. In the Mediterranean, mirages ("Fata Morgana") allow it. Still it would not reach 200 km.
  23. Jump up But Temple only had a later edition based on an English translation of 1658. He was unable to get his hands on the 1558 first print.
  24. Jump up Abat, Bonaventure: "Amusemens Philosophiques sur Diverses Parties des Sciences, et Principalement de la Physique et des Mathematiques" (Philosophical Diversions concerning Various Types of Sciences, and Principally of Physics and Mathematics), Amsterdam and Marseilles, 1763, Diversion VI, pp. 361-414. (Acc. Temple)
  25. Jump up Temple (2000), p. 165f
  26. Jump up Libri, Guillaume: "Histoire des Sciences Mathematiques en Italic depuis la Renaissance des ettres," (History of the Mathematical Sciences in Italy since the Renaissance, to the Close of the Seventeenth Century), Paris, 1835. Acc. Temple: "The second edition was published in 1838, and I use its page numbers: see pp. 46-9."
  27. Jump up Temple (2000), p. 166f (with translation)
  28. Jump up The whole citation given by Temple from Burke (1928): "As the wisdom of God is ordained for the direction of the universe, so is this science of vision evidently and beneficially ordained for its beauty. I shall give some examples both of refraction and reflection... Similarly mirrors might be erected on an elevation opposite hostile cities and armies, so that all that was being done by the enemy might be visible. This can be done at any distance we desire, since, according to the book on Mirrors [he presumably means the Catoptrica attributed to Euclid; see Propositions 13-15], one and the same object can be seen by means of as many mirrors as we wish, if they are placed in the manner required. Therefore they can be placed more closely and more remotely, so that we might see an object as far off as we pleased. For in this way Julius Caesar, when he wished to subdue England, is said to have erected very large mirrors, in order that he might see in advance from the shore of Gaul the arrangement of the cities and camps of England." Bacon, Roger, The Opus Majus of, translated by Robert Belle Burke, University of Pennsylvania Press, Philadelphia, 2 vols, 1928, Vol. II, pp. 580-2.
  29. Jump up This was explained to me by a physicist. At least two mirrors with different type of deformation are necessary. Only this deformation, a curvature, is important for the optical quality. A lens telescope needs a curvature and a homogeneous glass body and is therefore technically more demanding. The curvature of the mirror could be simplified with mathematical talent. Some suitable curvatures can be created if a flat plate is joint to a hollow body and subjected to positive or negative pressure to create a membrane deformation. An astronomer created a very complicated curvature in the early 20th century using this method - he only had one hand. The most perfect telescopes today are used by governments and have three curved mirrors.
  30. Jump up The final limit for magnification is air turbulence. It is worse in daytime and near ground. Even a perfect optic today is usually limited to what a 150 mm can do.
  31. Jump up I heard a suggestion that larger ones could allow both eyes to look through like binoculars. But doubts came up whether the eyes would get images that matched.
  32. Jump up So by William Camden: Britannia, London (1586)
  33. Jump up The "very large" description suggests he only had a secondary or tertiary account.
  34. Jump up According to "Chronicle of the Twenty-Four Generals" mentioned in: Roger Bacon, Thomas S. Maloney: "Compendium of the study of theology", Leiden (1988) p. 8
  35. Jump up The whole citation in Temple (2000), p. 126f
  36. Jump up See the Secret Courts record of 1490 ("Kapitel zum Oberfeimgericht zu Arnsberg") in Thudichum, Friedrich: Femgericht und Inquisition, Gießen (1889), pp. 14ff. Excerpts and comments here.