Popular Science Monthly/Volume 71/July 1907/Illustrations of Medieval Earth-Science



C'est vers le Moyen Age énorme et délicat,
Qu'il faudrait que mon cœur en panne naviguât.
Paul Verlaine.

MODERN experimental science dates only from the sixteenth century. The habit of interrogating nature, the application throughout all departments of research of the observational and inductive methods, the thirst for fresh discovery and invention, and the irrepressible curiosity that inquires into the innermost recesses of the wonderful world we live in, seeking to ascertain its laws and acquire mastery over its forces—all these leading characteristics of modern science were absent from its medieval prototype.

In reality, the so-called science of the middle ages is scarcely worthy of the name. Infinitely inferior as compared with modern science, it was still more crude, more distorted, more fantastic and illusory than that of ancient times. Medieval man had no clear-eyed perception of the visible world, actuality possessed for him little value, that which really is and happens was without special significance in his eyes. What the medieval man saw he interpreted as a symbol, what he heard he understood as an allegory. Dante himself is our best witness that cultivated men of his age esteemed the speculative life vastly superior to the practical.

Under the conditions of hopeless barbarism that existed from the seventh to the eleventh century there could be no real culture, and intellectual activity continued at an extremely low ebb. Religion absorbed almost all other occupations of the mind, faith was exalted as a sovereign virtue, mere empirical knowledge was disdained and rejected. As the Christian religion became the leading subject of men's thought and interest, so the principal business of their lives throughout the middle ages was the salvation of their souls. External conditions were unpropitious, subjective conditions inhibitory for the development of scientific ideas. Hence it was inevitable that learning should become decadent, and the proud record of ancient achievement forgotten. Indeed, as early as the fourth century of our era, before all relics of the old culture had disappeared, Eusebius wrote:

It is not ignorance which makes us think lightly of science in general, but contempt for its useless labor, while we turn our souls to better things.

Two centuries later Pope Gregory the Great protested against the study of pagan literature,

because the praise of Christ and the praise of Jove are not compatible in one mouth.

Again in the tenth century, a period of utter stagnation, illumined by scarcely a ray from classical antiquity, church dignitaries maintained that

the successors of St. Peter wish for their teachers neither Plato nor Virgil, nor Terence, nor any other of the philosophic cattle.

But with the revival of learning during the next two hundred years came a change for the better, and medieval knowledge began to assume a more positive character. Its science, still contaminated with the errors and superstitions it had received from remote ages, gradually became less chaotic, less fantastic and symbolic, less dominated by theology, although for a long time after its subjection to scholastic influences it remained, so to speak, Aristotelized. That is to say, logical analysis was relied upon for ascertaining all manner of truth, a complete system being devised toward that end by Raymond Lull. The independent searching out and testing of actual facts, the process of drawing general conclusions from concrete phenomena, were not the methods employed by medieval schoolmen, with the one notable exception of Roger Bacon.[1] It was commonly held that all truth may be obtained by the use of reasoning alone; and "that by analyzing and combining the notions which common language brings before us, we may learn all that we can know. Thus logic came to include the whole of science." (Whewell.)

There can be no doubt that the universal reverence for Aristotle's authority, and blind acceptance of other accredited doctrines and treatises, greatly retarded scientific progress. All men begin their development with a childlike trust in authorities and examples, and as science had to be regenerated de novo toward the end of the middle ages, it is only natural that its beginnings should appear to us lamentably weak and puerile. Moreover, the system of instruction employed by Catholic schoolmen was not conducive to real enlightenment. The real difficulty, as has been pointed out, is that "not life and nature were the basis of instruction and science, but books. Not the thing itself was the object of inquiry, but the word; not experiment disclosed the truth, but dialectics." Authority had greater weight than arguments, and in the last resort authority depended more upon a master's reputation than on his knowledge. Finally, we must not forget the restraint imposed upon medieval philosophy by theology. Religious discipline required that the results of human reason should be conformable to church dogmas and woe to him who dared insinuate that whatever was taught by the church was not also the logical outcome of human reasoning.

Thus, freedom of the intellect had to contend not only with formidable difficulties imposed from without, but with no less effective hindrances, wrong conceptions and limitations that came from within. While these conditions lasted the net result was sterility. In time, however, that innate longing to escape the bonds of ignorance, that patient and zealous striving after truth which stimulates all lofty endeavor, these impulses gradually became more assertive; and, triumphant at last, gave rise to our modern critical science.

It would be impossible to attempt here even a superficial sketch of the remarkable rise and expansion of empirical knowledge that took place during the twelfth and thirteenth centuries, by virtue of which Dante's era merits its appellation of secolo d'oro. The innumerable commentaries that have been devoted to the most striking figure of the middle ages attest the difficulty of preparing an adequate survey of contemporary knowledge. Remember, too, that the peerless poet stands out from the midst of a notable company of erudite laymen and clerical scholars. It will be sufficient to recall only such names as those of Ser Brunetto Latini, whom Dante expressly calls his 'master,' and whose encyclopedic work embraces practically all the science of his time; Albertus Magnus, often styled the "Universal Doctor," and his famous disciple, St. Thomas Aquinas; those brilliant Anglican geniuses. Roger Bacon and William of Ockham, forerunners of the modern spirit of investigation; and those twain Italian luminaries whose souls were fired with the glow of ancient and of the newly revived culture, Petrarch and Boccaccio. Still earlier, and entirely independent of Christian influences, the Arabian circle of sciences had gained new luster from Averroës, its chief exponent and adornment.

But besides these greater lights there shone many of feebler intensity, yet none the less worthy of grateful esteem, since their combined rays helped toward clearness of vision. There was one erudite scholar, for instance, who was formerly rated as a mere imitator and plagiarist of Albert of Bollstädt; whereas we now know that the reverse was true, in that the master drew largely upon his disciple for materials in preparing his huge compendium on natural history. This was Thomas of Cantimpré, who wrote during the third and fourth decades of the thirteenth century, and whose works were widely read and translated. His chief contribution to science was a treatise entitled "De naturis rerum," which served at once for the source and model of Conrad of Megenburg's "Buch der Natur," the earliest of its kind to be written in the German vernacular.-

Conrad, however, considerably amplified the work of his Brabant predecessor, and is further interesting to us for displaying power of original observation. He had also the happy faculty of meditating upon his observations, and was by no means averse to offering his own explanation of the causes of various phenomena. Accordingly, it has seemed worth while to reproduce a passage from this author relating

Albertus Magnus.

to earthquakes, for the reason that it offers a very fair presentment of the status of geological speculation among medieval schoolmen. The second illustration has been selected with similar intent from the "Cosmography" of Ristoro of Arezzo, written in 1282. Dante's acquaintance with Ristoro's work has not been definitely proved, but is regarded by competent authorities as highly probable.[2]

On the Nature and Causes of Earthquakes

(Extract from Conrad of Megenburg's "Buch der Natur," 1359)

The fourth and nethermost element is the sphere of earth. Its distance from the firmament [of the fixed stars], as determined by divers scientific men, both pagan and Christian, is 309,375 miles. No one can impugn the accuracy of this result, depending as it does upon laborious calculation and the reduction of very delicate astronomical observations. None but unlettered folk contemn such investigations. Ignorant persons are unable to comprehend that a geometer may station himself outside the town and accurately determine the height of turrets within the town by means of angular measurement. Yet in sooth is it possible. By a similar method we ascertain the distance from earth to the starry heavens.

The earth is the only one of the four elements that is favorably adapted for man; it is peculiarly his province, as heaven is the habitation of God and the angels. The earth element alone is innocuous to man, the others often injure him. For water drowns, foul air suffocates, and fire consumes him. The earth is by nature cold and dry, externally harsh, yet concealing within its bosom full many beauteous things, such as precious stones and the noble metals. By a like token, many an humble citizen may possess jewels within his heart. The earth-realm is very luxuriant, and the only one that brings forth fruit in abundance. How many miles it measures in circumference, and the extent of its diameter, I have already set forth in another place,[3] and likewise have explained the cause thereof, why it does not fall away from its abode in space. As the heart is lodged within the mid-portion of the body, so is hell seated at the center of the earth. Thus do our reverend masters instruct us.[4]

Oft it happens that the earth trembles, causing cities to fall, and mountains to crash together. Simple folk know not the reason of this, but foolishly believe that the earth is borne up by a mighty fish, which carries his tail in his mouth; and the turning or moving about of this creature causes the earth to shake. But this is a myth.[5] Remains for us to give true relation of this marvel, and to explain the cause of its occurrence. Now earthquakes originate in this manner, that within subterranean cavities, and especially in the interior recesses of moun- tains, vapors are compacted together in such vast quantities, and under such tremendous pressure, as to exceed at times all means for restrain- ing them. They crowd in all directions against the walls of the in- terior caverns, fly from one to another of them, and continue to aug- ment in volume until they have surcharged an entire mountain. The increase of these vapors is occasioned by the stars, especially by Mars and Jupiter. When now the vapors are confined for a long period within the subterranean cavities, their pressure becomes so prodigious that they burst forth with enormous violence and rend mountains asunder. Even when they fail to break completely through the crust they are yet able to produce a severe shock.

There are two kinds of earthquakes. Those of the first sort cause a gentle swaying of the ground like the rolling of a ship at sea. This movement is least destructive of fortresses and houses. The reason for this is that the vapors upheave the crust in a single supreme effort, and thereupon relapse in energy. Disturbances of the second sort are those which produce tremblings of the crust by means of a succession of sudden shocks, the motion being comparable to that of hand-shaking. Their effect upon buildings is most disastrous, solid masonry being shattered and hurled down by them. The process involved in this class of earthquakes is that one vapor rushes in pursuit of another, and drives it violently from side to side.

That the causes are verily as we have described is supported by abundant evidence. First, when a catastrophe is about to happen, pre- monitory rumblings are heard that resemble nothing so much as the noise of an hundred thousand hissing serpents, stridulating in chorus; or again there may be bellowings like unto those of maddened bulls. These sounds proceed from the violent agitation of the vapors within the interior of the earth, forcing their way through crevices and struggling to become liberated. Secondly, the sun shines feebly, or appears reddish-hued by day, owing to the heavy pall of smoke that rises from the earth's surface and obscures the view. Thirdly, it is well known that immediately after an earthquake the air becomes virulent, so

that many people die. The reason for this is that when the vapors have been confined for a long time underground they become fetid and noxious. The same thing happens in wells that have long remained foul and choked up, for when these are again opened for cleansing purposes, the first workmen to descend into them are often asphyxiated.

Many wondrous effects are wrought by earthquakes. Note first that the vapors escaping at such times frequently transform men and beasts into stone, especially into rock-salt, and this is very liable to happen in mountainous regions or in the vicinity of salt-mines. This lapidifying property of the vapors is due to their enormous condensation. So affirm the eminent doctors of science. And I myself have heard it reported that high up in the Alps as many as fifty neatherds with their beeves were turned to stone in this manner; with them also was a dairymaid engaged in drawing milk, and transfixed in that attitude at the selfsame moment when all were petrified. Note secondly that earthquakes are often accompanied by flames and glowing ashes which shoot up from below and ignite houses, villages and towns. Yet a third accompaniment of earthquakes is the belching up from below of vast quantities of sand and dust, sufficient to engulf whole cities.

Concerning the Processes of Mountain Formation

(From Book VI., Chapter 8, of Ristoro d'Arezzo's "Composizione del Mondo," 1282)

And we have ourselves discovered and excavated near the summit of an exceedingly high mountain remains of numerous species of fish and other creatures, such as various members of the shark tribe, and even shells that had retained traces of their original coloration. And in the same locality are found also different varieties of sand, gravel, water-worn pebbles and boulders scattered about in great profusion, apparently deposited by aqueous agency: and this we consider proof that the mountain in question was formed by the flood.

And we have at another time ascended a lofty mountain whose summit was composed of a thick stratum of very hard rock, of ferruginous color, and whose structure was as clearly the work of design as a vase is evidence of the potter's art. A huge castle, almost a citadel in fact, rested upon cliffs of this formation, and all the strata outcropping at that altitude reposed upon other beds that had plainly been formed by water action. And the proof thereof consists in this, namely that as one examines the strata exposed along the flanks of the mountain, one finds in certain places earth commingled with sand, at others tufa along with stones rounded by water action, and again elsewhere, quantities of fish remains belonging to various species, and also numerous other beds of divers kinds; all of which proves that this particular mountain, and the others already mentioned, near whose summits occur fish remains, were formed by the deluge. Yet this same catastrophe may very readily have formed other mountains which do not contain sand and fish remains, the difference being occasioned by the nature of sediments existing in particular localities. Such, then, is the process of mountain-making. And the reason why mountain chains must have been formerly sea-bottom, or deposited in marine basins [before their upheaval], is that the volume of fossiliferous and arenaceous sediments is far too considerable to be ascribed to the agency of rivers, or of any other body of water inferior to the sea itself. . . .

[The continuation of this passage is devoted to seismic and volcanic phenomena, which are discussed more particularly in a subsequent section (Distinzione vii. parte iv.). The author expresses himself upon these questions, as well as upon the meaning of fossils, erosive action of water in molding land surfaces, scintillation of the stars, etc., in eminently scientific manner. His elder contemporaries, Albertus Magnus and Vincent of Beauvais, also note the existence and teaching of fossil remains. Similar inferences are drawn by Cecco d'Ascoli, the ill-fated author of l'Acerba and envious rival of Dante in the latter part of the thirteenth and first quarter of the fourteenth century.]

  1. On Baconian contributions to science, see Professor Holden's interesting article in Popular Science Monthly for January, 1902 (60: 255).
  2. A modern German edition of the text was published by H. Schulz in 1897. The most recent study of Thomas Cantipratanus is by a Dutch author, Dr. W. A. Van der Vet, entitled "Het Bienboëc van Thomas van Cantimpré," 1902.
  3. Conrad's data as to the dimensions of the earth and its distance from the several heavens are possibly derived from the same source as Dante's and Brunette Latini's, namely, the Elementa Astronomica of Alfraganus, cap. xxi. Roger Bacon's calculation of the earth's circumference was only one-fourteenth smaller than the truth, and Ristoro's independent reckoning of the latitude of Arezzo, in 1282, was in error to the extent of little more than one degree.
  4. S. Thomas Aquinas teaches with regard to hell that it is probably situated under the earth and that its fire is of the same kind as terrestrial fire, an ignis corporeus. (Summa theol., Suppl., Pars iii., Qu. 97.)
  5. Probably an echo of ancient Titan myths, though having affinity also with the Arabian voyages of Sinbad. The existence of a great sea-monster was a very popular legend in the middle ages, the creature being sometimes identified as Cetus (the whale), or the Craken of the north, or again merely as a gigantic fish. In the bestiary of Philippe de Thaun the incident is given in a few lines beginning:
    "Cetus ceo est mult grant beste, tut tens en mer converse,
    Le sablun de mer prent, sur son dos l'estent."

    The monster reappears under the name of Jascom or Jasconius in the old Celtic legend of St. Brandan:

    "Jascom he is i-cleped, and fondeth nite and dai
    To putte his tail in his mouth, ac for gretnisse he ne mai."