More literally, Going toward the south and veering toward the north, veering, veering goes the wind; and to its veerings the wind returns.

"The wind is continually whirling about, and the wind returneth upon its whirlings."
It is plain, from the clause which I have restored to the fifth verse, that the author refers to the approximations of the sun to the northern and southern tropics, viz., of Cancer and Capricorn.
All the versions agree in applying the first clause of the sixth verse to the sun, and not to the wind. Our version alone has mistaken the meaning. My old MS. Bible is quite correct:
The sunne riisith up, and goth doun, and to his place turnith agein; and there agein riising, goth about bi the south, and then agein to the north.
The author points out two things here:
1. Day and night, marked by the appearance of the sun above the horizon; proceeding apparently from east to west; where he sinks under the horizon, and appears to be lost during the night.
2. His annual course through the twelve signs of the zodiac, when, from the equinoctial, he proceeds southward to the tropic of Capricorn; and thence turneth about towards the north, till he reaches the tropic of Cancer; and so on.

The (e) wind goeth toward the south, and turneth about to the north; it whirleth about continually, and the wind returneth again according to its circuits.
(e) By the sun, wind and rivers, he shows that the greatest labour and longest has an end, and therefore there can be no happiness in this world.

The wind goeth toward the south, and turneth about unto the north,.... The word "wind" is not in this clause in the original text, but is taken from the next, and so may be rendered, "it goeth towards the south", &c. that is, the sun (x) before mentioned, which as to its diurnal and nocturnal course in the daytime goes towards the south, and in the night towards the north; and as to its annual course before the winter solstice it goes to the south, and before the summer solstice to the north, as interpreters observe. And the Targum not only interprets this clause, but even the whole verse, of the sun, paraphrasing the whole thus,
"it goes all the side of the south in the daytime, and goes round to the side of the north in the night, by the way of the abyss; it goes its circuit, and comes to the wind of the south corner in the revolution of Nisan and Tammuz; and by its circuit it returns to the wind of the north corner in the revolution of Tisri and Tebet; it goes out of the confines of the east in the morning, and goes into the confines of the west in the evening.''
But Aben Ezra understands the whole of the wind, as our version and others do, which is sometimes in the south point of the heavens, and is presently in the north;
it whirleth about continually; and the wind returneth again according to his circuits; which may be meant of the circuits of the sun, which has a great influence on the wind, often raising it in a morning and laying it at night; but it is the wind itself which whirls and shifts about all the points of the compass, and returns from whence it came, where the treasures of it are. Agreeably to Solomon's account of the wind is Plato's definition of it,
"the wind is the motion of the air round about the earth (y).''
This also exemplifies the rotation of men and things, the instability, inconstancy, and restless state of all sublunary enjoyments; the unprofitableness of men's labours, who, while they labour for riches and honour, and natural knowledge, labour for the wind, and fill their belly with east wind, which cannot satisfy, Ecclesiastes 5:16; as well as the frailty of human life, which is like the wind that passes away and comes not again; and in this respect, like the rest of the instances, exceed man, which returns to its place, but man does not, Job 7:7.
(x) Jarchi, Alshech, and Titatzak, interpret it of the sun; so Mercerus, Varenius, Gejerus; accordingly Mr. Broughton renders it "he walketh to the south." (y) Definition. p. 1337. Ed. Ficin.

according to his circuits--that is, it returns afresh to its former circuits, however many be its previous veerings about. The north and south winds are the two prevailing winds in Palestine and Egypt.

"It goeth to the south, and turneth to the north; the wind goeth ever circling, and the wind returneth again on its circuits." Thus designedly the verse is long-drawn and monotonous. It gives the impression of weariness. שׁב may be 3rd pret. with the force of an abstract present, but the relation is here different from that in 5a, where the rising, setting, and returning stand together, and the two former lie backwards indeed against the latter; here, on the contrary, the circling motion and the return to a new beginning stand together on the same line; שׁב is thus a part., as the Syr. translates it. The participles represent continuance in motion. In Ecclesiastes 1:4 the subjects stand foremost, because the ever anew beginning motion belongs to the subject; in Ecclesiastes 1:5 and Ecclesiastes 1:6, on the contrary, the pred. stands foremost, and the subject in Ecclesiastes 1:6 is therefore placed thus far back, because the first two pred. were not sufficient, but required a third for their completion. That the wind goes from the south (דּרום, R. דר, the region of the most intense light) to the north (צפון, R. צפן, the region of darkness), is not so exclusively true of it as it is of the sun that it goes from the east to the west; this expression requires the generalization "circling, circling goes the wind," i.e., turning in all directions here and there; for the repetition denotes that the circling movement exhausts all possibilities. The near defining part. which is subordinated to "goeth," elsewhere is annexed by "and," e.g., Jonah 1:11; cf. 2-Samuel 15:30; here סבב סובב , in the sense of סביב סביב, Ezekiel 37:2 (both times with Pasek between the words), precedes. סביבה is here the n. actionis of סבב. And "on its circuits" is not to be taken adverbially: it turns back on its circuits, i.e., it turns back on the same paths (Knobel and others), but על and שׁב are connected, as Proverbs 26:11; cf. Psalm 19:7 : the wind returns back to its circling movements to begin them anew (Hitzig). "The wind" is repeated (cf. Ecclesiastes 2:10; Ecclesiastes 4:1) according to the figure Epanaphora or Palindrome (vid., the Introd. to Isaiah, c. 40-66). To all regions of the heavens, to all directions of the compass, its movement is ceaseless, ever repeating itself anew; there is nothing permanent but the fluctuation, and nothing new but that the old always repeats itself. The examples are thoughtfully chosen and arranged. From the currents of air, the author now passes to streams of water.

The wind - The wind also sometimes blows from one quarter of the world, and sometimes from another; successively returning to the same quarters in which it had formerly been.