Of Waves
The wave is the recoil of the stroke and it will be greater or less in proportion as the stroke is greater or less. A wave is never alone but is mingled with as many other waves as there are inequalities on the banks where the wave is produced. . . .
If you throw a stone into a pond with differently shaped shores all the waves which strike against these shores are thrown back towards the spot where the stone struck; and on meeting other waves they never intercept each other’s course . . . a wave produced in a small pond will go and return many times to the spot where it originated. . . . Only in high seas do the waves advance without recoil. In small ponds one and the same stroke gives birth to many motions of advance and recoil. The greater wave is covered with innumerable other waves which move in different directions; and these are deep or shallow according to the power that generated them. . . . Many waves turned in different directions can be created between the surface and the bottom of the same body of water at the same time . . . all the impressions caused by things striking upon the water can penetrate one another without being destroyed. One wave never penetrates another; but they only recoil from the spot where they strike.
16
When the wave has been driven on to the shore by the force of the wind it forms a mound by putting its upper part at the bottom and turns back on this until it reaches the spot where it is beaten back anew by the succeeding wave which comes from below and turns it over on its back, and so overthrows the mound and beats it back again on the aforesaid shore, and so continues time after time, turning now to the shore with its upper movement and now with its lower fleeing away from it. . . . If the water of the sea returns towards the bed of the sea after the percussion made upon its shore, how can it carry the shells, molluscs, snails, and similar things raised from the bottom of the sea and leave them upon this shore? The movement of these things towards the shore commences when the percussion of the falling wave meets the reflex wave, for the things raised from the bottom often leap up in the wave that bounds towards the shore, and their solid bodies are raised in the mound which then draws them back towards the sea; and so continues the succession until the storm begins to abate, and they are left stage by stage where the greater waves had reached and deposited the booty which they carried, and the succeeding waves did not reach the same mark. There remain the things cast up by the sea.
13
A wave of the sea always breaks in front of its base, and that portion of the crest will then be lower which before was highest.
17
The spiral or rotary movement of every liquid is swifter in proportion as it is nearer to the centre of its revolution. This is a fact worthy of note, since movement in a wheel is so much slower as it is nearer to the centre of the revolving object. . . .
18
[
With a drawing showing water taking the form of hair.
]
Observe the motion of the surface of the water, how it resembles that of hair, which has two movements—one depends on the weight of the hair, the other on the direction of the curls; thus the water forms whirling eddies, one part following the impetus of the chief current, and the other following the incidental motion and return flow.
19
The centre of a particular sphere of water is that which is formed in the tiniest particles of dew, which is often seen in perfect roundness upon the leaves of plants where it falls; it is of such lightness that it does not flatten out on the spot where it rests, and it is almost supported by the surrounding air, so that it does not itself exert any pressure, or form any foundation; and because of this its surface is drawn towards its centre with equal force from every side; and so each part runs to meet another with equal force and they become magnets one of another, with the result that each drop necessarily becomes perfectly spherical, forming its centre in the middle, equidistant from each point of its surface; and as it is pulled equally by each part of its gravity, it always places itself in the middle between opposite parts of equal weight. But when the weight of this particle of water comes to be increased, the centre of the spherical surface immediately leaves this particular portion of water, and moves towards the common centre of the sphere of the water; and the more the weight of this drop increases the more the centre of the said curve approaches towards the centre of the world.
20
If a drop of water falls into the sea when it is calm, it must of necessity follow that the whole surface of the sea is raised imperceptibly, seeing that water cannot be compressed within itself like air.
21
2. WATER AND EARTH
The surface of the sphere of water does not move from its circuit round the centre of the world which it invests at an equal distance. And it would not move from this equidistance if the earth, which is the support and the vase of the water, did not rise above it, away from the centre of the world.
The earth is moved from its position by the weight of a little bird alighting upon it.
The surface of the sphere of the water is moved by a little drop of water falling into it.
22
It is of necessity that there should be more water than land, and the visible portion of the sea does not show this; so that there must be a great deal of water inside the earth, besides that which rises into the lower air and which flows through rivers and springs.
23
Amid all the causes of the destruction of human property, it seems to me that rivers hold the foremost place on account of their excessive and violent inundations. If anyone should wish to uphold fire against the fury of impetuous rivers, he would seem to me to be lacking in judgement, for fire remains spent and dead when fuel fails, but against the irreparable inundation caused by swollen and proud rivers no resource of human foresight can avail; for in a succession of raging and seething waves gnawing and tearing away high banks, growing turbid with the earth from ploughed fields, destroying the houses therein and uprooting the tall trees, it carries these as its prey down to the sea which is its lair, bearing along with it men, trees, animals, houses, and lands, sweeping away every dike and every kind of barrier, bearing along the light things, and devastating and destroying those of weight, creating big landslips out of small fissures, filling up with floods the low valleys, and rushing headlong with destructive and inexorable mass of waters. What a need there is of flight for whoso is near!
Oh, how many cities, how many lands, castles, villas, and houses has it consumed!
How many of the labours of wretched husbandmen have been rendered idle and profitless! How many families have been ruined and overwhelmed! What shall I say of the herds of cattle which are drowned and lost! And often issuing forth from its ancient rocky beds it washes over the tilled (fields). . . .
24
(
a
) The Deluge and Shells
Since things are far more ancient than letters, it is not to be wondered at if in our days no record exists of how these seas covered so many countries; and if moreover such record ever existed, the wars, the conflagrations, the deluges of the waters, the changes of languages and of laws, have consumed every vestige of the past. But sufficient for us is the testimony of things produced in the salt waters and found again in the high mountains, far from the seas of today.
25
In this work of yours you have first to prove that the shells at a height of a thousand braccia* were not carried there by the Deluge, because they are seen at one and the same level, and many mountains are seen to rise considerably above that level; and to inquire whether the Deluge was caused by rain or by the swelling of the sea; and then you must show how, that neither by rain which makes the rivers swell, nor by the overflow of the sea could the shells, being heavy objects, be driven by the sea up the mountains or be carried there by the rivers contrary to the course of their waters.
26
You now have to prove that the shells cannot have originated if not in salt water, almost all being of that sort; and that the shells in Lombardy are at four levels, and thus it is everywhere, having been made at various times. And they all occur in valleys that open towards the sea:
27
Shells and the reason of their shape
The creature that resides within the shell constructs its dwelling with joints and seams and roofing and various other parts, just as man does in the house where he dwells; and this creature expands the house and roof gradually as its body increases, since it is attached to the sides of these shells. Therefore the brightness and smoothness of these shells on the inner side is somewhat dulled at the point where they are attached to the creature that dwells there, and its hollow is roughened, in order to receive the knitting together of the muscles by means of which the creature draws itself in when it wishes to shut itself up within its house. And if you wish to say that the shells are produced by nature in these mountains by means of the influence of the stars, in what way will you show that this influence produces in the same place shells of various sizes and varying age, and of different kinds?
Shingle
And how will you explain to me the fact of the shingle being all stuck together and lying in layers at different altitudes on the high mountains? For here there is to be found shingle carried from various parts to the same spot by the rivers in their course; and this shingle is nothing but pieces of stone which have lost their sharp edges from having been rolled over for a long time, and from the various blows and falls which they have experienced during the passage of the waters which have brought them to this spot.
28
If the Deluge had carried the shells for distances of three and four hundred miles from the sea it would have carried them mixed with various other natural objects all heaped up together; but even at such distances from the sea we see the oysters all together and also the shellfish and the cuttlefish and all the other shells which congregate together, found all together dead; and the solitary shells are found apart from one another as we see them every day on the seashores.
And we find oysters together in very large families, among which some may be seen with their shells still joined together, indicating that they were left there by the sea and that they were still living when the strait of Gibraltar was cut through. In the mountains of Parma and Piacenza multitudes of shells and corals with holes may be seen still sticking to the rocks. . . .
Underground and under the deep excavations of stone quarries timbers of worked beams are found which have already turned black. They were found in my time in those diggings at Castel Fiorentino. And these were buried in that deep place before the sand deposited by the Arno in the sea which then covered the plain had been raised to such a height, and before the plains of Casentino had been so much lowered by the removal of the earth which the Arno was continually washing away from there. . . .
The red stone of the mountains of Verona is found all intermingled with shells turned into this stone; some of them have been sealed at the mouth by the cement which is of the substance of the stone; and in some parts they have remained separate from the mass of the stone which enclosed them; because the outer covering of the shell had intervened and prevented them from uniting; and in other places this cement had petrified the old broken outer covering.
And if you were to say that these shells have been created and still constantly are being created in such places by the nature of the locality and through the potency of the heavens in those spots, such an opinion cannot exist in brains of any extensive powers of reasoning, because the years of their growth are here numbered upon the outer coverings of the shells; and large and small ones may be seen, and these would not have grown without food and could not have fed without motion, and here they would not be able to move.
29
And if you should say that it was the Deluge that carried these shells away from the sea for hundreds of miles, this cannot have happened since the Deluge was caused by rains; because rains naturally force the rivers towards the sea with the objects carried by them, and they do not draw up to the mountains the dead things on the seashores.