ABSTRACT
The early quantification of the catchment water balance in the 17th Century has been well documented. But there is one book called “L’Hydrographe” or “La Science des Eaux” that was published by a Jesuit priest, Père Jean François, in Rennes in 1653 (20 years before the publication of Pierre Perrault’s De l’Origine des Fontaines) that has been largely overlooked. The book is split into 4 parts that deal with the formation, movement and mixing of waters and the origin of springs. Further parts were published with La Science des Eaux that deal with the arts of surveying and drawing of maps, the construction of canals and fountains, with a final part on doing arithmetic with integer and real numbers “with pen and counters”. François was convinced, much more than Perrault, that the waters of springs was the result of rainfall and snowmelt.
Disclaimer
As a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also.Introduction
The study of water has always been of very practical interest. Water supply and irrigation schemes date back to pre-historic civilisations (see, for example, Biswas, 1970) and must surely have been based on empirical studies of sustainable sources of water and management of water resources developed as the result of long practical experiences over generations. It is probably also the case that this led to speculation about the hydrological cycle in ways that were only transmitted orally. The ancient Greek philosophers recorded some of that speculation in written form (e.g. Koutsoyiannis and Mamassis, 2021) but it was not until the 17th Century that the first experimental studies of catchment hydrology started to be made, notable by Pierre Perrault (1608-1680) and Edmé Mariotte (1620-1684). Perrault, in his book De L’Origine des Fontaines of 1674, considers some of the past thinkers about the hydrological cycle, from Seneca onwards, including one Père Jean François who, 21 years before had published a book called La Science des Eaux in FrenchFootnote1.
The contribution of Jean François receives only a passing mention in the History of Hydrology book by Asit K. Biswas (Biswas, 1970, p228), perhaps because, unlike the work of Perrault and Mariotte, there was not a translation into English readily available. This article aims to remedy that, and make the work more widely known, with a focus on the perceptual model of Jean François. As far as I can tell, there has never been an English translation made of the work, so in what follows all the extracts cited are my own tentative translations. This has not proven to be too difficult once the obstacles of 17th Century fonts and spellings have been resolved in transcription, but there may remain some issues about the exact meaning of the words used at that time. I have, therefore, made an interpretation that seems to convey the hydrological meaning of the text.
Père Jean François et La Science des Eaux
Not a lot is known about the life of Père Jean François, though he does have a page on fr.wikipedia.org where he is categorised as a mathematicianFootnote2. He is thought to have been born around 1582 in St. Claude in the Comté de Bourgogne under the name of Jean Charnage, and to have died in 1668 in Rennes in Brittany. He became a member of the Compagnie de Jesus in 1605 and taught in a number of Jesuit colleges, including the Collège de la Flèche that he joined in 1613. Perhaps the most important thing known about him is that he was there a teacher of René Descartes (1596-1650) who seems to have held him in high regard1.
In 1650, at the age of 68, he was sent to the Collège de Rennes where he spent the last 18 years of his life. Aurèle La Rocque, the translator into English of De l’Origine des Fontaines by Pierre Perrault mentions in a footnote in his translation of 1967 that René Kerviler (René Mathurin Marie Pocard du Cosquer de Kerviler (1842-1907) an engineer who became a bibliographer and was very active in the Société des Bibliophiles Bretons), had written about Jean François in a paper of 1893, but he had not been able to see a copy. This appears to be a commentary on François’ La Science des Eaux published in Kerviler (1893) who notes particularly its references to Brittany, but also the approach to science of Jean François. François is mentioned only very briefly in the relevant volume of the multi-tomed work about the literature of Brittany that was initiated by Kerviler in 1886 (Kerviler et al., 1903) where it is stated that, although most of his works were first published in Rennes, he was not actually Breton by birth but a Franc-Comtois. A full list of publications by François is given in de Backer and Sommervogel (1869) ()Footnote3.
Table 1. The publications of Père Jean François (taken from de Backer and Sommervogel, 1869)
It will be seen from that his writings were concentrated in a few short years after he had arrived at the Collège de Rennes. Indeed, in his first book, La Science de Géographie, he wrote: “My dear reader, I am starting to publish at the age of 65 years, when others have already finished” ().
Figure 1. The beginning of the Avis au Lecteur, taken from Jean François, La Science de la Géographie, 1652. The printed text of La Science des Eaux is similar in fonts and spellings. Copied from the version available on Gallica of the Bibliothèque Nationale de France (available at https://galica.bnf.fr, accessed 27.08.2023).
His major work on hydrological matters is La Science des Eaux (The Science of Waters) published in Rennes in 1653. The book was reprinted in Paris in 1654Footnote4. In fact, the book contains two title pages (). The main title page gives the full title as La Science des Eaux, qui explique en quatre parties leur formation, communication, mouvements & mélanges; Avec les Arts de conduire les eaux, et mesurer la grandeurs tant des eaux que des terresFootnote5. The second, which precedes a Preface, is also of interest in that it reads: L’Hydrographe, c’est-à-dire, La Science des Eaux et des sources naturelles jointe avec les Arts et Les Conduites des Eaux. L’Hydrographe here seems to refer to hydrography, in the sense that, while dealing primarily with water, some later parts of the work refer to surveying and the drawing of maps and plansFootnote6. The 1653 and 1654 versions of the complete book consist of 11 parts (), versions of some of which (from the paginations) seem to have also been published separately. Only the first 4 parts are labelled as Parties of La Science des Eaux. They are each split into several chapters and sections (). The remaining sections on Les Arts of working with water include techniques for surveying and making canals and fountains, for raising water to higher levels, with a final part on doing arithmetic with integer and real numbers “with pen and counters”.
Table 2. The main sections of La Science des Eaux.
Table 3. The chapter headings of the first 4 parts of La Science des Eaux. Note that the headings of the main text (which have no Chapter V) are slightly different to those in the initial List of Contents (which has no Chapter III)).
Figure 2. Title page of La Science des Eaux as published in Rennes in 1653 with summary of contents. Copied from the version available on Gallica of the Bibliothèque Nationale de France (available on Gallica of the Bibliothèque Nationale de France, https://gallica.bnf.fr/, accessed 28.11.2023). A later edition was published in Paris in 1654 and is available on https://archive.org/.
Figure 3. Title page: L’Hydrographe, c’est à dire, La Science des Eaux et des sources naturelles jointe avec les Arts et Les Conduites des Eaux (together with the start of the Preface). Copied from the 1653 version available on https://gallica.bnf.fr/ of the Bibliothèque Nationale de France (accessed 28.11.2023).
The approach to science of Jean François
shows that Jean François differentiates La Science from Les Arts, but, as he explains at the beginning of the Preface:
“There is no better way of arriving at perfection in Science than the experiences obtained by Practice, nor to come to perfection in Practice than to know the reasoning that the Sciences provide; because those experiences in Practice confirm the understanding from Science and give them a high degree of certainty; and the reasoning of the Sciences leads Practice in all circumstances, and puts it in an eminent degree of infallibility.”
(La Science des Eaux, Preface, p.1).
He goes on to suggest that the lack of knowledge of both Science and Practice has led some to make mistakes in the management of Springs and the construction of either private or public water fountains, that which he aims to correct in La Science des Eaux, “to join La Science to Les Arts of water, and practice to reason”. He also wants to demonstrate the wonder of L’Art Divin, so necessary to the health of people and suggests that if human practice can imitate nature as the Divine, then Science will be joined with Practice to the benefit of both.
In his application of these principles, François attempts to base his understanding and explanations of the science of water on his experience in practical water management. Where he cannot provide a good explanation, then he prefers to confess ignorance, and defer to the Divine. This is the case in the extended discussion of what he calls the “flux” and “reflux” of the sea (the tides), for which he gives a variety of estimates of amplitude from different places in the world (some of which are rather impressively high, such as the 70 pieds at St. Malo and St. Michel in Brittany, or ~ 22.7m). He wonders about why freshwaters (he mentions Lake Huron and other large lakes) do not seem to have the same tidal response as salt waters, suggesting that the salt might have a similar effect to the yeast in bread. After considering several suggested causes, he prefers an explanation based on the movement of the moon, but for which he does not have a good rationalisation (see also the extended discussion in Part 3, §7, p.65ff)Footnote7. However, he comments about cause and effect of the tides at this point:
“And so if we still see a link between the Celestial and Elementary bodies, or between nature and the cause of such an effect, that is enough for us to see that it follows from such a conjunction and conformity of one movement with the other: so that is the sole means for us to know the effects that follow from certain causes.”
(La Science des Eaux, p.72).
The Perceptual Hydrological Model of Jean François for the origin of Springs
At the time that La Science des Eaux was published, the hydrological cycle was still the matter of significant speculation. It would be another 20 years before Pierre Perrault would publish his De L’Origine des Fontaines (Perrault, 1674; La Rocque, 1967) with the first quantitative estimates suggesting that rainfalls were more than sufficient to sustain normal river flows over a year. Perrault was not always right in his hydrological intuition, however, even though his arguments were based on some careful observation and experimentation (see Nace, 1974; McDonnell et al., 2024). In the first part of De L’Origine des Fontaines, Perrault reviews the work of past authors, including Vitruvius, Bernard Palissy, Pierre Gassendi, Jean François and René Descartes. He assigns all to the “common opinion” that rainfall supplies the water for springs, but argues against this proposition on the basis that he has not observed rainfalls penetrating the soil to sufficient depths to be able to recharge subsurface storage (see also McDonnell et al., 2024).
It is therefore of interest to examine the underlying understanding of hydrological processes of Jean François, what we would now call his perceptual model (e.g. Beven, 1987, 2002). François makes it quite clear right from the very start of La Science des Eaux that he has no need to differentiate between different types of waters:
“I presuppose as very certain, that he who knows the process by which the nature shapes a drop of water, knows also the way in which all the water of the Sea is made, since this is none other than an accumulation of many drops: either because nature has no other way of acting for one or another: It is the same for all as for one: as it is also the same water produced everywhere: i.e. because nature cannot produce water other than successively and only in the shape of drops only. It cannot produce more than one drop at a time in any place … .”
“And it must not be thought that those great rivers that discharge into the Sea by 7 mouths such as the Nile, by 72 like the Volga, or which have 70 leagues (lieuës) in width where they reach the Sea such as the river of the Amazons, can have exited the earth all at once and in the same way as they enter into the Sea. It is the continuous work and contribution of 4 to 500 leagues in length and 40 to 50 in width of the land through which these rivers pass. They are enlarged by the confluence of several large rivers; these by the arrival of others lesser rivers; and these are formed of many Streams; and these have their small Springs; and those their threads of Water; which then have drops of water gathered together. Here is what has been found by those who have been sufficiently curious to explore the lands and discover the first principles of the Water Springs.”
(La Science des Eaux, Part 1, Ch.1, §1, p.1/2).
It is notable that François demonstrates a wide knowledge of the geography of the world throughout this work, having already published La Science de la Géographie in 1652.
Again, later in §8 “De la cause des Sources & des Fontaines”:
“A River is not different from a Stream nor the Sea from a Lake, only in the matter of the quantity of elemental water. And given that Springs are the causes of all the mass visible and the effects of the invisible, it is on this point that Springs are at the origin of particular discussion in Physics.”
(La Science des Eaux, Part 1, Ch. 1, §8, p.25).
He notes that “this particular discussion” has divided opinion and summarises the explanations of the causes of springs into three types:
“The first is that of those who believe that Springs come directly from the water of the Sea, depositing their salt as they pass through the earth, and occurring in Springs with the water density, to then flow straight to the Sea by a sort of perpetual motion. The second is the opinion of those who see the waters formed from vapours either in the earth or in the air, that is to say the rain and snowmelt which infiltrate into the Earth and re-emerge, and in re-emerging create new Springs. The third is the opinion of those who add to that of the second type air converted into water and think that the greater part of the waters are created in this way. The Holy Scriptures appear to favour the first explanation, experience the second, and reasoning (la raison) the third.“
(La Science des Eaux, Part 1, Ch. 1, §8, p.25).
This reflection on the different explanations of Holy Scriptures, experience and reasoning seem bold for this time, especially for a Jesuit priest. This perhaps reflects his age and experience, as well as the revolution in scientific thinking that was already occurringFootnote8.
Jean François then gives his reasons for preferring the second opinion at some length.
“The supporters of the second explanation appeal to evident and frequent experience. We see, they say, that most Springs, Wells, Rivers flow, increase, decrease, and cease according how to the rain and snowmelt flow; increase, decrease and cease according to how the Sun causes more or less evaporation. And given that there is hardly any rain in Egypt, and several places in Africa, it follows that there are also hardly any Springs apart from a rare one. But if a country lacks water produced in place, it can receive an abundance which comes from afar. The reason is that the earth, being porous, receives the rain and melt into it, and having taken as much as they need let the rest of these waters descend sideways where they find a gradient and free passage, and where they are attracted by others lower down which flowing and leaving the place allowing others to replace them and fill the space.”
(La Science des Eaux, Part 1, Ch. 1, §8, p.26).
He also suggests that this is supported by experiment (experience):
“The experiment is that of three masters of engineering and fountains, who having dug deeply into the earth to see the first origin of Springs, both common and mineral, have not encountered anything other than Springs that come from diverse trickles and small drops of water which were not more visible. These three are Francine, De Rochas and one who has for title of his book Des Oeuvres FigulinesFootnote9 . And all those who dig ditches or wells for gathering water, find Springs everywhere in different quantities right up to places where the very first drops are found, recognise this truth and make it clear; Because one discovers from these first origins of all the waters that we have without need to raise it higher, and without having to acknowledge any remnant coming from the Sea.”
(La Science des Eaux, Part 1, Ch. 1, §8, p.29).
His explanations of where the water comes from in the earlier §§ (pp3-6), deal primarily with the evaporation of water from the seas and its transfer through the air by winds to the land. He understands that the same water can be changed from liquid to vapour form by evaporation and converted back to liquid by condensation.
“You can make this balanced change directly visible if you set up an Alembic with the tube to receive the water made from the rising vapour rise and take the water back to the Cornüe or Cucurbite where it was first put: you can see the perpetual change of the water into vapour and the vapour into water and consequently a movement upwards of the water turned into vapour and downwards of the vapour reduced to water, which gives a perfect image of our concept of Springs”
(La Science des Eaux, Part 1, Ch. 1, §8, p.27/28).
He also understands that water does not lose its salinity when it is filtered through the earth (p.20), his main reason for rejecting the first explanation. A second reason, like Perrault after him, is his belief in an impermeable layer at some depth in the soil, made up “of clay, of stone, of compacted earth (conroy) that God has placed almost everywhere close to the surface to stop the waters and limit their descent” (p.26), which also must then serve as a barrier to vapours rising from below, not only water but also those “smokes, pestilent and pernicious to man, such as Mixtures, Metals, Mercuries, Acids, Sulphurs etc” (p.26). He makes the exception of where God has left cavities and cracks to allow “exhalations, flames and smokes” to escape (without using the word volcano here, but elsewhere he refers to the eruption of Hekla in Iceland (p18), Etna and the Eolian Islands, Vesuvius, “Le Volcan de Mexic” and other volcanos, (p.24, see also §7 and Part 2,Ch.3)).
He also turns to his own ends an important argument previously used in favour of the first explanation based on the Scripture citation from Proverbs 8 Dum librarat fontes aquarium which he translates as “When the waters of the Springs are in balance” (p.27). The same reference provides that the seas should not overflow. He notes that a simpler explanation for maintaining such a balance than allowing water to come directly from the sea, is to allow for the vapours lost by evaporation from the Seas to be replaced by the flow of water from the rivers supplied by springs. Thus:
“This explains the persistence of the Sea in neither filling or drying: and all together the Springs in their way can explain the Holy Scriptures because if the vapours which come from the water can change back into water, as well as the Sea change its waters into vapour, so can the vapours bring water to the earth, which then returns to the Sea: and thus the Sea conceives the Springs by means of the vapours provided by its waters and the Springs provide the Seas by means of the vapours they receive and which they send to the Seas.”
(La Science des Eaux, Part 1, Ch. 1, §8, p.27)
François also notes how the idea of balance requires transfers between the oceans by currents, since there has to be more evaporation from the seas in the “Zone Torride” than in the “Zone Froide”.
In Part 1, Chapter 1, §3, François discusses the complementary causes of evaporation and condensation. For evaporation he suggests heat (la Feu), movements of the air causing rarefaction, and the natural principle that the air must be of low density (“une grande rarité”) (p.4/5). For condensation, it is the inverse: cold, compression of the air, and the principle that water has its natural density. What seems to be missing from his explanation of the hydrological cycle is the role of clouds in moving water in the air by the winds to where it is later precipitated but the first suggestion that clouds are made up of water droplets was made by the contemporary German physicist, Otte von Guericke (1602-1686). This was not published, however, until 1672 after François had diedFootnote10. In Part 1, Chapter 1, §4 François discusses three places where drops of water might be formed from vapour: in the air, at the surface of the ground and under the ground. In the air he finds the right conditions:
“ … in the middle region of the Air, because it is there where the Vapours leaving the Waters and the Earth are found, where they stop and cannot rise higher because they find the Air less dense, where they are pressed by those that follow or are above, where they are cooled by the internal principle of their matter, of the Water that they have within them, either because the environment is very cold, or because an opposing wind brings them and presses them together; and others that are pushed against solid objects such as mountains and rocks; and others which slow their speed which are causes of condensation cited above, from which follows the effects that we seek, that is the formation of Waters in the Air. From that it follows that the rain is more abundant in the Zone Torride … because of the multitude of Vapours attracted by the perpendicular rays of the Sun. And if they arrive sometimes by night in some places, such as the Isles du Sein Mexic, it is because of the perversity of the winds which raise them”
(La Science des Eaux, Part 1, Ch. 1, §4, p.8)
Thus he describes the right sort of processes without invoking clouds. The other two locations for the condensation of water from vapour are more problematic. He suggests that water in the atmosphere can be attracted (“sont attires”) by the water already in the pores and cavities of the soil. He has some evidence for this in the fact that mountainsides exposed to humid air from the west in France have more springs than those facing east because there is both more water condensed at the surface and more rainfall. Also on islands, such as “Guarde-Louppe”, where there is more water with elevation because they intercept the winds that have not already discharged their vapours. He gives other geographical evidence including “the abundance and verdure of the vegetation” (p.9), and the condensation over bodies of water, such as in “Zayre d’Affrique” and “Le Catay de l’Asie”.
For sources of water under the ground, he cites a mountain in “L’Eclaunie” called “Odmiloost”, where thick plumes of vapour escape from openings in the ground. Between 13 and 35 days after each eruption, various springs around the mountain that water the lower slopes stop flowing because of the vapours being allowed to escape in this way (analogous to making a hole in an Alembic allowing the steam to escape). He also cites the Chartreux monks in Paris, whose millstream ran dry following the exploitation of a neighbouring quarry. Having bought the quarry and sealed the openings allowing the vapours to escape, the spring feeding the millstream started to flow again. He acknowledges that these vapours cannot be produced by the heat of the sun, but suggests that the heat of the earth (“chaleur Elementaire”) would suffice.
Section §5 discusses the role of the earth. He distinguished 3 types of materials: sandy, which allow water to flow freely; clay or compacted which do not allow any flow; and porous or spongy, which retain a part of the water but also let part flow through. He expands on the admirable properties of each. He also notes that slope is important, on sloping ground part of the water will be retained and part will flow downslope (p. 13), but he also remarks:
“The difficulty is to see what the Subsurface Waters do: and here I conceive it thus. The Water that is either formed in the Earth’s Surface, or received from rain and snowmelt, must be stopped in those places where there is the 2nd type of material, enter into the earth at least in part in other places more or less quickly according to whether the pores are more or less big, and will descend until they are stopped by the highest compacted layer (“une terre de conroy”) … . Secondly, when the water descends to depth or flows by some slope through these pores, it is little by little, drop by drop, and only in particular places: because it does not feel a great pressure from water above that is held by the soil, nor a great attraction from water below; and in addition there is a resistance to flow through such small pores. And it is by the Divine Providence that this slowness of movement allows us to have water during droughts and for entire months without rain, which we see in the wells and Springs which reduce little by little during such times”.
(La Science des Eaux, Part 1, Ch. 1, §5, p.13)
In the end he does not completely rule out the third explanation of Springs (that of Air being turned into water) because “it is a common opinion” but suggests that this might only happen in small quantities since any air changed into water must be compensated by water changing into air, with the corresponding changes in properties. Even if there was some fortuitous (accidental) process that allowed that to happen, it could only do so with difficulty.
The causes of Springs which appear or disappear suddenly
In the final section of Part 1 of La Science des Eaux, François discusses springs that start or stop flowing all of a sudden. He first evokes a form of uniformitarianism:
“ … because while the causes producing waters in a place stay the same, so the effects must also stay the same and not stop flowing having always done so, or appear having never been seen before. This axiom is surely self-evident and therefore I hold that it must find some change in those places where there is some change to the Springs.”
(La Science des Eaux, Part 1, Ch. 1, §9, p.32)
He then provides some reasons why there might be sudden changes. The first is the possibility of a landslide that extends over the pathway of the water.
“because the weight of earth can block and constrain the waters from using their primary outlet, and take a new pathway that leads to place different from the first: and this change will cause sadness to those who are deprived of their Spring and happiness to those others who find themselves favoured; and the astonishment of both.“
(La Science des Eaux, Part 1, Ch. 1, §9, p.32)
He then notes that this can also happen after earthquakes which can block the pathways of water, or by the digging of wells that attract water from higher elevations (see next section). Finally he cites Theophrastes who adds to this:
“ … the cultivation of the earth, that which is worked receives the water of the rain in joy, but those which are abandoned become hard and rejects it, that which he says arrived to the inhabitants of a town in Arcadia who leaving their lands fallow saw the Sources lost, but by restarting their cultivation saw them reappear. Others believe that planted trees are capable of taking the waters from certain places for their sustenance, so that they must be uprooted to reestablish the Springs, but that must be the case only in places where water is lacking to see such an effect, normally there is enough to sustain the trees and plants and provide Springs.”
(La Science des Eaux, Part 1, Ch. 1, §9, p.32)
The effect of earthquakes on springs and streams is still the subject of contemporary research (e.g. Montgomery and Manga, 2003; Wang and Manga, 2010).
Underground cavities and groundwater in La Science des Eaux
Part 1, Chapter 1, §6 deals with water and underground cavities which François considers essential for the transfer of water. “Without then, all transfers would stop, & by consequence all production, & nature cannot allow such idleness to occur without acting” (p..15). He then distinguishes two types of cavities: pipes (“tuïaux”), which can also allow the escape of smokes and vapours and allow water to descend; and the others like moulds (matrices) that serve as shops (boutiques) for nature to make a variety of works (this is explained later as the forms found in limestone caverns “with many figures of columns, helmets, tombs, and other grotesques and games of nature” (p.19), as well as blowholes in cliffs, with a variety of examples).
The first type is of interest here, in that he suggests that the pipes may be small, medium or large. The smallest allow water to enter the earth and descend until reaching some clay layer. All earth and stone that dries out has such pores. It is this water that fills the cavities of wells and can make a spring but “in parallel can allow vapours to escape in great quantities” (p16). In winter, it is suggested, the cold will close up the surface, and those vapours will condense, providing more water.
Medium sized pores include those cracks found in quarries, and pathways where waters flow in threads and underground streams. This can result in springs created by water coming from a distance, and is seen in wells “where the water appears visibly in the form of threads or streams” (p.16)Footnote11. Indeed, he notes that for an effective well it is necessary to have connected and frequent cavities.
François has already demonstrated some understanding of subsurface hydrology in §5 where he notes that where there are wells above an impermeable level they will all rise and fall in the same way. But if you withdraw water from a well, then this will lower the levels in surrounding wells, “that which one does more quickly and in greater quantity when it is necessary to clean a well” p.14). Also, if one digs a well wider or deeper than the others then it will attract the water, more for the nearest than those further away, after which if the level is lower than a surrounding well it will be dry “because the water of the others finds a means to descend … and never rises” (p.15). He even suggests that you can check on the connection between wells by lowering one and checking on the level in othersFootnote12 or whether they all rise and fall together. If that is the case, it suggests that the impermeable layer is continuous. He also notes that it is difficult to avoid such connectedness in towns where there are lots of houses with wells.
Returning to §6 he suggests that the largest pipes can provide passageways for large rivers, entire lakes and even seas to be connected. He gives a number of examples where rivers are observed to disappear underground, including the “le Tigre en Mesopotamie, Lycus en Asie, le Niger en Affrique, le Nil en Egypte, Guardiana en Espagne, from where comes the proverb that a bridge over it can pass 100000 sheep” (p16), together with a number of examples in France. His examples become a little more problematic when he refers to the connections between seas, which he says he has proved in Ch. 16 §6 of his Science de la Géographie. The first example he gives, however, is that of the Dead Sea that is filled by the River Jordan but has no outlet so must connect to the Mediterranean by an underground passage (this would, we now know, require the water to flow uphill). He also suggests that the Caspian Sea must have underground connections to the Mediterranean, since even allowing for evaporation, there are more rivers providing water than the capacity of the outflow; while there must also be an even larger subsurface connection between the Mediterranean and the Red Sea.
Parts 2 to 4 in La Science des Eaux
As noted earlier, a particular point of interest in Part 1 of La Science des Eaux is that Jean François, while a Jesuit priest, is open to new interpretations of the quotations from the Bible in his understanding of the hydrological cycle, in the light of what he calls “evident and frequent experience” (p.26). Part 2, however, as explained in its Preface, is intended to demonstrate the perfection of La Nature, the Arts Divines and Le Tout-Puissant in distributing water over the surface of the earth and how man should aim to imitate that perfection in his works with water in “the number, the extent, the order, the symmetry and the perfection of the effects that follow” (p. 33).
In what follows, François writes of the creation of the earth, and how it is not necessary to seek any other cause for the disposition of nature, including the cavities of seas and lakes than “the divine will as controlled by the infallible rules of the divine spirt and divine art” (p.37). He does allow, however, that man can modify nature as in Holland and other places “where the sea has already been excluded by dykes, locks and roadways to extend the limits and make some progress on the earth”. (p.37).
He also attributes the transfer of vapour to produce rain far inland as a divine gift, particularly in places where there is normally little rainfall. He notes in particular the inundations such as on the Nile, which require an extraordinary mass of water either from rain or from snowmelt “which is none other the rains of many days, weeks or months” (p.40). In France, the “Loyre” can be more like a torrent than a river, and can rise so quickly in winter, fed by the waters of the Mountains of the Auvergne. He suggests that we need to know three variables (dimensions) to be able to predict (conjecturer) the magnitude of such inundations: the duration of the rains, their extent and the mass of snow, as well as allowing for the time necessary for the water to flow from source to where they go overbank (p.48)Footnote13.
There is not space here to discuss the rest of Parts 2 to 4 in more detail. They are full of geographical examples that illustrate both the natural occurrences of water (and fire), and their use by man. Part 3 deals with the movements of water, particularly knowledge of currents in the oceans and the tides (Chapter IV) and the movements of freshwaters including and explanation of the rise and falls of lakes using the example of a syphon (Chapter VI, p85). Part 4 deals with the mixing of different types of waters, including hot springs, salt waters and mineral springs (Chap. Sixiesme). There is much more to be explored in these Parts.
Conclusions and significance of La Science des Eaux
La Science des Eaux of Jean François provides a fascinating glimpse into the understanding of the hydrological cycle and hydrological processes in the middle of the 17th Century, some 20 years before the quantitative estimates of the catchment water balance by first Pierre Perrault in 1674 and then by Edmé Mariotte in the work finished by Phillipe de la Hire and published posthumously in 1686. Jean François takes us into that world of speculative reasoning of the time, but (with our centuries of hindsight) in many respects he was more correct than Perrault in his understanding of processes (see Nace, 1974; McDonnell et al., 2024). His wide range of geographical examples is remarkable, even if his interpretations were not always correct about the possible underground connections between water bodies but, as he noted himself, “the difficulty is to see what Subsurface Waters do … .” (p.13), something that we still struggle to overcome even with modern geophysical methods. Also remarkable is some of the issues of water management that he discusses in passing, such as the degradation of abandoned land reducing infiltration; the idea that trees will reduce water yields; the capture of water by a nearby deeper well; issues that are still relevant today.
It has to be said that the text is rather repetitive and Aurèle La Rocque in a footnote to his translation of Perrault, remarks that the style of Jean François had been described as “not so agreeable” (La Rocque, 1967, p185). This, almost certainly, reflects his style and experience as a teacher in the various Jesuit colleges he was assigned to during his career, though the inconsistent numbering of chapters, sections and points in some places suggests that he was also writing quickly and could have done with a better proof-reader. Here I have examined in detail only the Sections in Part 1 which contain the essential elements of the perceptual model of Jean François. There is still surely more interesting historical insight to be found in the remainder of the text.
Acknowledgments
I have very much appreciated the suggestions of Christophe Cudennec who took the time not only to read and comment the text but also to search out the 1653 edition of Les Sciences des Eaux and compare with some of my translations. Despite his good advice, I have left some inconsistencies in the modernisations of spellings and capitalisations so as to provide a balance between the flavour of the original 17th Century French and clarity.
Notes
1 De l’Origine des Fontaines was originally published anonymously. See Dooge (1959) for a discussion of how Pierre Perrault came to be considered as the author.
2 https://fr.wikipedia.org/wiki/Jean_François_(mathématicien). This gives a link to the Bibliothèque Nationale de France (BNF), but the link is broken and I have not been able to find the source.
3 De Backer and Sommervogel also include a posthumous work published in Paris in 1690 which may have been misattributed in that the title page describes the anonymous author as a Bourgeois of Paris.
4 The translations here are based on the version published in Rennes in 1653 and available on https://gallica.bnf.fr/ (last accessed 28.11.2023, see ). The 1654 Paris reprint is available at https://archive.org, last accessed 10.10.2023. The book itself appears to be rather rare. A copy was recently listed at a price of $8500 and it appears to have only come up for auction three times since the 1970ʹs.
5 The spelling of the original has been updated in some of the longer French transcriptions for clarity.
6 On p.58-59 François refers to the work L’Hydrographie by Père Fournier and other authors (also written as L’Hydrographe on p.70). This seems to a reference to the book by the Jesuit priest Père Georges Fournier, L’Hydrographie, contenant la théorie et la pratique de toutes les parties de la navigation, published by Michel Soly in Paris in 1643. Thus, although little in La Science des Eaux has to do with navigation, it is not clear if François intended to differentiate between L’Hydrographe (hydrographer as hydrological scientist) and L’Hydrographie (hydrography as mapping the oceans and navigation).
7 Though in Part 2 p.48 he notes that the Ancient Saxons knew and counted the periods of the moon by means of the tides, which is presumably a reference to the explanation of the tides in On the Reckoning of Time by the Venerable Bede which appeared in England in around 703.
8 The books of René Descartes, Discourse on the Method (1637) and Principles of Philosophy (1644) had already appeared and would certainly have been known to François as his former teacher.
9 Perhaps a reference to the type of pottery called Figuline (from the Latin figulina) but can also refer to the clay from which pottery is made (des oeuvres Figulines in original)? Bernard Palissey who had written about the origin of springs 70 years earlier in his book, Discours admirables, de la nature des eaux et fonteines of 1580, was a master of ceramics by Royal appointment with the title “Inventeur des rustiques figulines du Roi”
10 Guericke studied the vacuum and invented the barometer to measure air pressure. It would seem that Guericke thought that rain was produced by the contraction of air due to cold, but he also experimentally produced precipitation by the rarefaction of moist air (see Middleton, 1966).
11 This may be one of the first mentions of preferential flow pathways in the soil in “scientific” hydrology.
12 This must be one of the first mentions of a drawdown test in “scientific” hydrology.
13 This must surely be one of the first suggestions of making hydrological forecasts in “scientific” hydrology!
References
- Beven, K.J. Towards a new paradigm in hydrology, In: Water for the Future: Hydrology in Perspective, IAHS Publ. No. 164, 393-403, 1987.
- Beven, K. J.Towards an alternative blueprint for a physically-based digitally simulated hydrologic response modelling system, Hydrol. Process. 16(2), 189-206, 2002.
- Backer, A. de and Sommervogel, Ch. Bibliothèque des écrivains de la Compagnie de Jésus, vol. 1, col.1940, 1869
- Biswas, A. K. History of Hydrology, North-Holland Amsterdam, 1970. (available at https://archive.org, last accessed 27.08.2023).
- Dooge, J.C.I. Un bilan hydrologique au XVIIe. siècle, La Houille Blanche, 45(6), 799-807, 1959.
- François, J. La science des eaux qui explique en quatre partie leur formation, communication, mouuemens, & meslanges; auec les arts de conduire les eaux, & mesurer la grandeur tant des eaux que des terres. Paris: chez Sebastien Piquet, au Palais, dans la Gallerie des Prisonniets à la Victoire, 1654 (available at https://archive.org, last accessed 10.10.2023)
- Guericke, O. von, Ottonis de Guericke experimenta nova (ut vocantur) Magdeburgica de vacuo spatio … , J. Janssonium at Waesberge, 1672.
- Kerviler, R. Armorique et Bretagne: recueil d’études sur l’archéologie, l’histoire et la biographie bretonnes, Tome 2 (pp.92-94 & p.102ff on La Science des Eaux), Honoré Champion Libraire, Paris, 1893. (available at https://gallica.bnf.fr/, last accessed 27.08.03)
- Kerviler, R. A. Apuril, X. De Bellevue, Ch. Berger, F. du Bois Saint-Sévrin, R. de l’Escoureillon, A. Gilebourg, P. Hémon, Fr. Jégou, Le Mée, A. Macé, A. Mauricet, A. Ménead, M. Nicol, R.&A. Ohein, Cte. De Pays, P. Paris-Jallobert, Peyron, J. Plihon, Pr. René, Cte. De Rosamordue, R. de St.-Meleu, Fr. Saulnier, C. Sommervogel, H. Soulas, Mle. De Surgères, G. de la Vieuxville, G. de Wimes etc. Répertoire général de bio-bibliographie bretonne. Livre premier, Les bretons. 14,FER-FRET. (p399/400 on Pr. J. François), 1903.
- Koutsoyiannis, D. and Mamassis, N. From mythology to science: the development of scientific hydrological concepts in Greek antiquity and its relevance to modern hydrology. Hydrology and Earth System Sciences, 25(5), 2419-2444, 2021.
- La Rocque, A. On the origin of Springs by Pierre Perrault, Hafner Publishing Company: New York, 1967 (available at https://archive.org, last accessed 27.08.2023)
- Mariotte, E. Traité du mouvement des eaux et des autres corps fluides, (translated into English by John Theophilus Desaquliers in 1718), 1686.
- McDonnell, J.J. Beven, K.J. Morgenstern, U. and Pfister, L. The first catchment water balance: New insights into Pierre Perrault, his perceptual model and his peculiar catchment, Hydrological Sciences Journal, this issue, 2024.
- Middleton, W. E. K. A history of the theories of rain, Franklin Watts Inc.: New York, 1966 (available at https://archive.org, last accessed 27.08.2023)
- Montgomery, D.R. and Manga, M. Streamflow and water well responses to earthquakes, Science, 300(5628): 2047-2049, 2003.
- Nace, R.L. Pierre Perrault: The man and his contribution to modern hydrology, Journal of the American Water Resources Association, 10(4), 633-647, 1974.
- Perrault, P. De L’Origine des Fontaines, Pierre le Petit, Paris, 1674 (available at https://archive.org, last accessed 27.08.2023)
- Wang, C.-Y. & Manga, M. Earthquakes and water. Springer: New York, 2010.