Lecture 1 — Opinions of the ancients on the origin of the sea and of its saltiness.

Let us explain the nature of the sea and the reason why such a large mass of water is salt and the way in which it originally came to be.

The old writers who invented theogonies say that the sea has springs, for they want earth and sea to have foundations and roots of their own. Presumably they thought that this view was grander and more impressive as implying that our earth was an important part of the universe. For they believed that the whole world had been built up round our earth and for its sake, and that the earth was the most important and primary part of it.

Others, wiser in human knowledge, give an account of its origin. At first, they say, the earth was surrounded by moisture. Then the sun began to dry it up, part of it evaporated and is the cause of winds and the turnings back of the sun and the moon, while the remainder forms the sea. So the sea is being dried up and is growing less, and will end by being some day entirely dried up. Others say that the sea is a kind of sweat exuded by the earth when the sun heats it, and that this explains its saltiness: for all sweat is salt. Others say that the saltiness is due to the earth. Just as water strained through ashes becomes salt, so the sea owes its saltiness to the admixture of earth with similar properties.

We must now consider the facts which prove that the sea cannot possibly have springs. The waters we find on the earth either flow or are stationary. All flowing water has springs. (By a spring, as we have explained above, we must not understand a source from which waters are ladled as it were from a vessel, but a first point at which the water which is continually forming and percolating gathers.) Stationary water is either that which has collected and has been left standing, marshy pools, for instance, and lakes, which differ merely in size, or else it comes from springs. In this case it is always artificial, I mean as in the case of wells, otherwise the spring would have to be above the outlet. Hence the water from fountains and rivers flows of itself, whereas wells need to be worked artificially. All the waters that exist belong to one or other of these classes. On the basis of this division we can see that the sea cannot have springs. For it falls under neither of the two classes; it does not flow and it is not artificial; whereas all water from springs must belong to one or other of them. Natural standing water from springs is never found on such a large scale.

Again, there are several seas that have no communication with one another at all. The Red Sea, for instance, communicates but slightly with the ocean outside the straits, and the Hyrcanian and Caspian seas are distinct from this ocean and people dwell all round them. Hence, if these seas had had any springs anywhere they must have been discovered.

It is true that in straits, where the land on either side contracts an open sea into a small space, the sea appears to flow. But this is because it is swinging to and fro. In the open sea this motion is not observed, but where the land narrows and contracts the sea the motion that was imperceptible in the open necessarily strikes the attention. The whole of the Mediterranean does actually flow. The direction of this flow is determined by the depth of the basins and by the number of rivers. Maeotis flows into Pontus and Pontus into the Aegean. After that the flow of the remaining seas is not so easy to observe. The current of Maeotis and Pontus is due to the number of rivers (more rivers flow into the Euxine and Maeotis than into the whole Mediterranean with its much larger basin), and to their own shallowness. For we find the sea getting deeper and deeper. Pontus is deeper than Maeotis, the Aegean than Pontus, the Sicilian sea than the Aegean; the Sardinian and Tyrrhenic being the deepest of all. (Outside the pillars of Heracles the sea is shallow owing to the mud, but calm, for it lies in a hollow.) We see, then, that just as single rivers flow from mountains, so it is with the earth as a whole: the greatest volume of water flows from the higher regions in the north. Their alluvium makes the northern seas shallow, while the outer seas are deeper.

Some further evidence of the height of the northern regions of the earth is afforded by the view of many of the ancient meteorologists. They believed that the sun did not pass below the earth, but round its northern part, and that it was the height of this which obscured the sun and caused night.

So much to prove that there cannot be sources of the sea and to explain its observed flow.

139. After determining concerning things generated on high, from either a dry evaporation or a moist vapor, and after adding a discussion about the generation of rivers on account of its similarity to the generation of rains, the Philosopher now begins to determine concerning things that come to be in the lower region from a dry exhalation. And it is divided into two parts:

in the first he determines about certain principal passions, at (353b5);

in the second about certain things which accompany them.

and here in the third book, at let us explain the remaining operations of this secretion (370b3).

The first is divided into two parts:

in the first he determines about the sea, whose saltiness is caused by dryness, at (353b5);

in the second about winds and the things caused by them, at let us proceed to the theory of winds (359b27).

140. The order which the Philosopher observes seems quite suitable. For after determining about things generated in the upper region of air from dry exhalation, namely, falling stars, comets, the milky circle and like things, he second determined about things generated in the lower region from moist exhalation, namely, rains and so on: and because rivers have a cause of their generation in the earth in the same way as rain in the air, after rains he determined about rivers. After this he determines about the sea, into which all rivers flow.

Concerning this, therefore, he first declares his intention (353a32) and says that we must speak now of the sea: namely, as to what its nature is, whether it is the natural place of water or is it by accident that water is gathered there; as to what is the cause of such an abundance of water's being salty; and of the primal generation of the sea, i.e., does it have a source of its generation and how?

141. second at the old writers who invented theogonies (353a34), he pursues his proposition, about which he does two things:

first, he presents the opinions of others about the sea, at (353a34);

second, he investigates the truth, at we must now consider the facts which prove that the sea (353b17).

Concerning the first he does two things:

first, he gives the opinions of ancient theologizers, at (353a34);

second, of the philosophers of nature, at others, wiser in human knowledge (353b5).

Regarding the first (353a34) one must know that before the times of the philosophers there were men called theologizing poets (such as Orpheus, Hesiod and Homer), because under the guise of fables they declared divine things to men. Concerning them, therefore, he says that they posited the sea to have springs of its own from which it is caused. They postulated this so as to avoid attributing to earth and sea extraneous principles not their own: for they believed the earth and sea to be most worthy of reverence, as though they were a great part of the whole universe; and they said that the whole heaven exists for the sake of earth and water and that that is why earth and water are surrounded by other bodies and by the heaven itself, as though this part were most worthy of honor and the first principle among all the bodies of the universe.

142. Then when he says, others, wiser in human knowledge (353b5), he presents the opinions of the natural philosophers concerning the sea and gives three opinions.

The first concerns the generation of the sea and he says that those wiser in human wisdom than the aforesaid poets (he says this because the naturalists dealt not with divine things, as did they, but with natural things, which is proper to human wisdom, i.e., conformed to the human intellect), said that the sea has generation. This is because from the beginning the entire region surrounding the earth was wet and full of water, but became dried out by the sun's evaporating the moisture: what evaporated, according to them, caused air and winds (and from this, they say, are caused the movement of the sun and moon and stars); what was left not yet dried up, is the sea. Hence they believe that by a continuous drying-up it is always shrinking, so that finally it will all be dried up and the sea exist no more. This is said to have been the opinion of Anaxagoras and Diogenes.

The second opinion is about the salt of the sea. For Empedocles said that the earth, warmed by the sun, exudes a certain sweat which, he believed, is the water of the sea. For this reason, so he says, the sea is salty, since the sweat of animals also is found to be salty.

The third opinion, that of Anaxagoras, also concerns the salt of the sea. He said that the earth through which the water passes, or which is mingled with the water, causes the salt of the sea: for just as something strained through ashes becomes salty, so the water of the sea becomes salty by an admixture of earth.

143. Then when he says, we must now consider the facts which prove that the sea (353b17), he searches for the truth regarding these opinions.

First, about the opinion of the theologizing poets (354a5);

second, about the opinions of the philosophers of nature, at we must now discuss the origin of the sea, if it has an origin (354b1).

About the first he does two things:

first, he shows that the sea has no springs, as they said, at (353b17);

second, he gives an answer to something seemingly contrary to his own argument, at it is true that in straits, where the land on either side contracts an open sea (354a5).

Concerning the first (353b17) he presents two arguments.

The first is that among the waters surrounding the earth, some can flow and some are stationary. Of those that flow it is plain that all are derived from springs. But this does not mean that the springs have as their source, as it were, a container holding a vast store of water, from which rivers are derived: it means, as already stated, that from the many places where it is formed little by little [drop by drop], the water comes together, and that it is by such confluence that it for the first time comes to be in so great a quantity. But with regard to stationary waters, some are collected and held in one place by something artificial or natural that obstructs the flow, and are called marshes or ponds. These differ by reason of largeness or smallness: for if a large store of water has been thus collected, it is called a pond; if a little, a marsh. Now, some stationary waters are fountainous, i.e., they subsist in their own source; all such are man-made, for example, wells. For all such waters thus stationary through art must have a spring, which would make them flow unless they were artificially prevented. Hence it is plain that all water from fountains and rivers flows of itself according to the inclination of nature, or, if it is to be stationary, must be made so artificially.

In the light of the foregoing it is plain that the water of the sea does not come from springs, because it falls within neither of the groups mentioned: it does not flow, as river water does, and we cannot say that it is man-made, as a well is. But all waters that come from springs either flow or are stationary by art—unless you include small bodies of water that stand of themselves and not artificially, as when flowing water finds its way into a hollow or meets an obstacle. But such water cannot exist in large amounts: because when the flow water increases, it must either run over the obstacle and start to flow again, or be submerged within the earth, as, we have said, happens in many places. Hence it cannot be said that such a quantity of water as the water of the sea could be standing of itself, if it arose from springs. The conclusion, therefore, is that the sea does not have springs.

144. He gives the second argument at again, there are several seas that have no communication (353b35), and says that there are many seas that have no communication with any other. For the Red Sea joins but slightly with the Ocean Sea beyond the columns of Hercules: from which sea the Hyrcanian and Caspian (which is the sea of Pontus) are far removed. If they had springs, the people who live along all the sides of the sea would not have failed to discover them. It is therefore not true that springs of the sea exist.

145. Then when he says, it is true that in straits, where the land on either side contracts an open sea (354a5), because a common flow is apparent in some seas, lest it be supposed that the sea can flow, as if proceeding from springs, the contrary of which he had supposed in the first argument, he assigns the cause of the flow seen in the sea. About this he does three things:

first, he shows why some sea flows, at (354a5);

second, he manifests what he supposed with a sign, at some further evidence of the height of the northern regions of the earth (354a27);

third, he summarizes at so much to prove that there cannot be sources of the sea (354a32).

Now he assigns three causes of the sea's flowing (354a5).

The first is that the sea flows because of its narrowness, where, from being a vast flood, it is confined into a small place because of being narrowed by adjacent land. Now the water of the sea is often moved back and forth, especially as a consequence of the movement of the moon, whose proper nature it is to agitate the moist: but this commotion of water in a large open sea goes unnoticed, but where it occurs in an area rendered small by the narrowness of the land it becomes more noticeable.

The second cause is that the sea which is contained within the columns of Hercules and does not communicate with any other sea (as was already said of the Sea of Pontus), that sea, I say, flows on account of the large number of rivers. And, for the same reason, one sea flows into another: for Maeotis flows into the Sea of Pontus and the Pontus into the Aegean. In other seas this is not so evident; but in the ones mentioned this happens on account of the number of rivers, for many rivers flow into them.

The third reason for the flow is that a sea covers a great deal of earth, in keeping with the quantity of the water, and one sea is not as deep as another; but the one that is not so deep always flows to the deeper one. Hence that sea to which another flows is always seen to be deeper: as, for example, the Pontus is deeper than Maeotis, the Aegean than the Pontus, and the sea of Sicily deeper than the Aegean; but the..Sofian and the Etruscan are the deepest of all. The sea beyond the Columns, however, is not deep, as is evident from the mud in the water flowing out of it. An indication of this is that it is calm, as though it were in a hollow. Therefore, just as individual rivers are seen flowing from higher to lower places, so in the sea, the flow is from the loftier places of the earth, which are in the north: consequently, the northern seas, from which water flows, are not as deep as those in the south which receive it.

146. Then when he says, some further evidence of the height of the northern regions of the earth (354a27), through a certain sign he manifests what he had said, namely, that the earth is higher toward the north. He takes as an indication of this the fact that some of the ancients believed that the sun did not go below the earth but only around it and that it became invisible at night because the northern heights obscured it.

Then when he says, so much to prove that there cannot be sources of the sea (354a32), he summarizes what he had said—and it is plain in the text.