7. Therefore we read: “  Let there be a firmament in the midst of the waters, and let it divide the waters from the waters .” I have said what the word firmament in Scripture means. It is not in reality a firm and solid substance which has weight and resistance; this name would otherwise have better suited the earth. But, as the substance of superincumbent bodies is light, without consistency, and cannot be grasped by any one of our senses, it is in comparison with these pure and imperceptible substances that the firmament has received its name. Imagine a place fit to divide the moisture, sending it, if pure and filtered, into higher regions, and making it fall, if it is dense and earthy; to the end that by the gradual withdrawal of the moist particles the same temperature may be preserved from the beginning to the end. You do not believe in this prodigious quantity of water; but you do not take into account the prodigious quantity of heat, less considerable no doubt in bulk, but exceedingly powerful nevertheless, if you consider it as destructive of moisture. It attracts surrounding moisture, as the melon shows us, and consumes it as quickly when attracted, as the flame of the lamp draws to it the fuel supplied by the wick and burns it up. Who doubts that the æther is an ardent fire?  41  So the “liquidissimus æther” of the Epicurean Lucretius (v. 501), “Suos ignes fert;” i.e. the fiery stars are of the nature of the element in which they move. cf. the Stoic Manilius i. 149, “Ignis in æthereas volucer se sustulit oras summaque complexus stellantis culmina cœli, Flammarum vallo naturæ mœnia fecit.” If an impassable limit had not been assigned to it by the Creator, what would prevent it from setting on fire and consuming all that is near it, and absorbing all the moisture from existing things? The aerial waters which veil the heavens with vapours that are sent forth by rivers, fountains, marshes, lakes, and seas, prevent the æther from invading and burning up the universe. Thus we see even this sun, in the summer season, dry up in a moment a damp and marshy country, and make it perfectly arid. What has become of all the water? Let these masters of omniscience tell us. Is it not plain to every one that it has risen in vapour, and has been consumed by the heat of the sun? They say, none the less, that even the sun is without heat. What time they lose in words! And see what proof they lean upon to resist what is perfectly plain. Its colour is white, and neither reddish nor yellow. It is not then fiery by nature, and its heat results, they say, from the velocity of its rotation.  42  So Aristotle, Meteor. i. 3, 30. ῾Ορῶμεν δὴ τὴν κίνησιν ὅτι δύναται διακρίνειν τὸν ἀ& 153·ρα καὶ ἐκπυροῦν ὥστε καὶ τὰ φερόμενα τηκόμενα φαίνεσθαι πολλάκις. Τὸ μὲν οὖν γίγνεσθαι τὴν ἀλέαν καὶ τὴν θερμότητα ἱκανή ἐστι παρασκευάζειν καὶ ἡ τοῦ ἡλίου φορὰ μόνον. What do they gain? That the sun does not seem to absorb moisture? I do not, however, reject this statement, although it is false, because it helps my argument. I said that the consumption of heat required this prodigious quantity of water. That the sun owes its heat to its nature, or that heat results from its action, makes no difference, provided that it produces the same effects upon the same matter. If you kindle fire by rubbing two pieces of wood together, or if you light them by holding them to a flame, you will have absolutely the same effect. Besides, we see that the great wisdom of Him who governs all, makes the sun travel from one region to another, for fear that, if it remained always in the same place, its excessive heat would destroy the order of the universe. Now it passes into southern regions about the time of the winter solstice, now it returns to the sign of the equinox; from thence it betakes itself to northern regions during the summer solstice, and keeps up by this imperceptible passage a pleasant temperature throughout all the world.

Let the learned people see if they do not disagree among themselves. The water which the sun consumes is, they say, what prevents the sea from rising and flooding the rivers; the warmth of the sun leaves behind the salts and the bitterness of the waters, and absorbs from them the pure and drinkable particles,  43  cf. Diog. Laert. vii. on Zeno. Τρέπεσθαι δὲ τὰ ἔμπυρα ταῦτα καὶ τὰ ἄλλα ἄστρα, τὸν μὴν ἥλιον ἐκ τῆς μεγάλης θαλάττης. So Zeno, Chrysippus, and Posidonius. thanks to the singular virtue of this planet in attracting all that is light and in allowing to fall, like mud and sediment, all which is thick and earthy. From thence come the bitterness, the salt taste and the power of withering and drying up which are characteristic of the sea. While as is notorious, they hold these views, they shift their ground and say that moisture cannot be lessened by the sun.  44  Pliny (ii. 103, 104) writes: “Itaque solis ardore siccatur liquor;…sic mari late patenti saporem incoqui salis, aut quia exhausto inde dulci tenuique, quod facillime, trahat vis ignea, omne asperius crassiusque linquatur: ideo summa æquarum aqua dulciorem profundam: hanc esse veriorem causam asperi saporis, quam quod mare terræ sudor sit æternus: aut quia plurimum ex arido misceatur illi vapore, aut quia terræ natura sicut medicatas aquas inficiat.” The first of these three theories was that of Hippocrates (De Aere, Locis, et Aquis, iv. 197) and of Anaximander (Plutarch περὶ τῶν ἀρέσκ, etc. ii. 552). On the second vide Arist., Prob. xxiii. 30. The idea of the sea being the earth’s sweat was that of Empedocles. cf. Arist., Meteor. ii. 1.

Διὰ τοῦτο Γενηθήτω στερέωμα ἐν μέσῳ τοῦ ὕδατος, καὶ ἔστω διαχωρίζον ἀνὰ μέσον ὕδατος καὶ ὕδατος. Εἴρηται τί τὸ σημαινόμενον παρὰ τῇ Γραφῇ τὸ τοῦ στερεώματος ὄνομα. Ὅτι οὐχὶ τὴν ἀντίτυπον καὶ στερέμνιον φύσιν, τὴν ἔχουσαν βάρος καὶ ἀντέρεισιν, οὐ ταύτην λέγει στερέωμα. Ἢ οὕτω ἂν κυριώτερον ἡ γῆ τῆς τοιαύτης κλήσεως ἠξιώθη. Ἀλλὰ διὰ τὴν φύσιν τῶν ὑπερκειμένων λεπτὴν οὖσαν καὶ ἀραιὰν καὶ οὐδεμιᾷ αἰσθήσει καταληπτὴν, στερέωμα τοῦτο ὠνόμασε, συγκρίσει τῶν λεπτοτάτων καὶ τῇ αἰσθήσει ἀκαταλήπτων. Καὶ νόει μοι τόπον τινὰ διακριτικὸν τοῦ ὑγροῦ: τὸ μὲν λεπτὸν καὶ διηθούμενον ἐπὶ τὰ ἄνω διιέντα, τὸ δὲ παχύτατον καὶ γεῶδες ἐναφιέντα τοῖς κάτω, ἵν' ἐξ ἀρχῆς μέχρι τέλους ἡ αὐτὴ εὐκρασία συντηρηθῇ, κατὰ μέρος τῆς ὑφαιρέσεως τῶν ὑγρῶν γινομένης. Σὺ δὲ τῷ μὲν πλήθει τοῦ ὕδατος ἀπιστεῖς, πρὸς δὲ τοῦ θερμοῦ τὸ πλῆθος οὐκ ἀποβλέπεις: ὃ κἂν ὀλίγον ᾖ τῷ μεγέθει, πολλῆς ἐστι διὰ τὴν δύναμιν ἀναλωτικὸν ὑγρασίας. Ἐφέλκεται μὲν γὰρ τὸ παρακείμενον ὑγρὸν, ὡς δηλοῖ ἡ σικύα: δαπανητικὸν δέ ἐστι τοῦ ἑλκυσθέντος κατὰ τὴν εἰκόνα τοῦ λυχνιαίου πυρὸς, ὃ διὰ τῆς θρυαλλίδος τὴν παρακειμένην τροφὴν ἐπισπασάμενον, ταχέως διὰ τῆς μεταβολῆς ἀπῃθάλωσε. Τὸν δὲ αἰθέρα τίς ἀμφιβάλλει μὴ οὐχὶ πυρώδη εἶναι καὶ διακαῆ; ὃς εἰ μὴ τῷ ἀναγκαίῳ τοῦ ποιήσαντος αὐτὸν ὅρῳ κατείχετο, τί ἂν ἐκώλυσεν αὐτὸν πάντα φλογίζοντα καὶ καταπιμπρῶντα τὰ συνεχῆ, πᾶσαν ὁμοῦ τὴν ἐν τοῖς οὖσιν ἐξαναλῶσαι νοτίδα; Διὰ ταῦτα ὕδωρ ἀέριον, νεφουμένου τοῦ ἄνω τόπου ἐκ τῆς ἀναφορᾶς τῶν ἀτμῶν, οὓς ποταμοὶ, καὶ κρῆναι, καὶ τενάγη, καὶ λίμναι, καὶ πελάγη πάντα προΐενται, ὡς ἂν μὴ πάντα πυρακτῶν ὁ αἰθὴρ ἐπιλάβοι: ὅπου γε καὶ τὸν ἥλιον τοῦτον ὁρῶμεν, ὥρᾳ θέρους διάβροχον πολλάκις καὶ τεναγώδη χώραν ἐν βραχυτάτῃ χρόνου ῥοπῇ ἄνικμον παντελῶς καὶ ξηρὰν καταλιμπάνοντα. Ποῦ τοίνυν ἐκεῖνο τὸ ὕδωρ; Δεικνύτωσαν ἡμῖν οἱ τὰ πάντα δεινοί. Ἆρ' οὐχὶ παντὶ δῆλον, ὅτι τῇ θερμότητι τοῦ ἡλίου διατμηθὲν ἀνηλώθη; Καίτοιγε οὐδὲ θερμὸν εἶναι τὸν ἥλιον ἐκεῖνοι λέγουσι: τοσοῦτον αὐτοῖς τοῦ λέγειν περίεστι. Καὶ σκοπεῖτε ποταπῇ ἀποδείξει ἐπερειδόμενοι πρὸς τὴν ἐνάργειαν ἀντιβαίνουσιν. Ἐπειδὴ λευκός ἐστι, φασὶ, τὴν χροίαν, ἀλλ' οὐχὶ ὑπέρυθρος, οὐδὲ ξανθὸς, τούτου ἕνεκεν οὐδὲ πυρώδης τὴν φύσιν: ἀλλὰ καὶ τούτου φασὶ τὸ θερμὸν ἐκ τῆς ταχείας εἶναι περιστροφῆς. Τί ἐντεῦθεν ἑαυτοῖς διοικούμενοι; Ὡς μηδὲν δόξαι τῶν ὑγρῶν ἀπαναλίσκειν τὸν ἥλιον. Ἐγὼ δὲ κἂν μὴ ἀληθὲς ᾖ τὸ λεγόμενον, ἀλλ' ὡς συγκατασκευάζον ἐμοὶ τὸν λόγον οὐκ ἀπωθοῦμαι. Ἐλέγετο γὰρ, διὰ τὴν ἐκ τοῦ θερμοῦ δαπάνην ἀναγκαῖον εἶναι τῶν ὑδάτων τὸ πλῆθος. Διαφέρει δὲ οὐδὲν, ἐκ φύσεως εἶναι θερμὸν, ἢ ἐκ πάθους ἔχειν τὴν πύρωσιν πρός γε τὸ τὰ αὐτὰ συμπτώματα περὶ τὰς αὐτὰς ὕλας ἀπογεννᾶν. Ἐάν τε γὰρ τριβόμενα ξύλα πρὸς ἄλληλα πῦρ καὶ φλόγα ἀνάψῃ, ἐάν τε ἐκ φλογὸς ἀναπτομένης κατακαυθῇ, ἴσον ἐστὶ καὶ παραπλήσιον ἐξ ἀμφοτέρων τὸ τέλος. Καίτοιγε ὁρῶμεν τὴν μεγάλην τοῦ τὰ πάντα κυβερνῶντος σοφίαν, μετατιθεῖσαν τὸν ἥλιον ἐξ ἑτέρων εἰς ἕτερα, ἵνα μὴ τοῖς αὐτοῖς ἀεὶ προσδιατρίβων, τῇ πλεονεξίᾳ τοῦ θερμοῦ λυμήνηται τὴν διακόσμησιν: ἀλλὰ νῦν μὲν αὐτὸν ἐπὶ τὸ νότιον μέρος κατὰ τὰς χειμερινὰς τροπὰς ἀπάγοντα, νῦν δὲ ἐπὶ τὰ ἰσημερινὰ σημεῖα μετατιθέντα, κἀκεῖθεν ἐπὶ τὰ προσάρκτια ὑπὸ τὰς θερινὰς τροπὰς ἐπανάγοντα, ὥστε τῇ κατὰ μικρὸν αὐτοῦ μεταβάσει τῷ περὶ γῆν τόπῳ τὴν εὐκρασίαν φυλάσσεσθαι. Σκοπείτωσαν δὲ εἰ μὴ αὐτοὶ ἑαυτοῖς περιπίπτουσιν, οἵ γε τὴν θάλασσαν λέγουσι μήτε πλημμυρεῖν τοῖς ποταμοῖς ἐκ τῆς τοῦ ἡλίου δαπάνης, καὶ προσέτι ἁλμυρὰν καὶ πικρὰν ἀπολείπεσθαι, τοῦ λεπτοῦ καὶ ποτίμου ὑπὸ τῆς θέρμης ἀναλωθέντος: ὅπερ ἐκ τῆς τοῦ ἡλίου μάλιστα γίνεται διακρίσεως, τὸ μὲν κοῦφον ἀπάγοντος, τὸ δὲ παχὺ καὶ γεῶδες οἷόν τινα ἰλὺν καὶ ὑποστάθμην ἐναφιέντος: ἐξ οὗ τὸ πικρὸν καὶ ἁλμυρὸν καὶ ξηραντικὸν τῇ θαλάσσῃ προσεῖναι. Οἱ δὴ ταῦτα περὶ θαλάσσης λέγοντες, πάλιν μεταβαλλόμενοι, μηδεμίαν τοῦ ὑγροῦ γίνεσθαι μείωσιν ἐκ τοῦ ἡλίου φασί.