SECT.  XIV.  Of the Air.

After having considered the waters, let us now contemplate another mass yet of far greater extent.  Do you see what is called air?  It is a body so pure, so subtle, and so transparent, that the rays of the stars, seated at a distance almost infinite from us, pierce quite through it, without difficulty, and in an instant, to light our eyes.  Had this fluid body been a little less subtle, it would either have intercepted the day from us, or at most would have left us but a duskish and confused light, just as when the air is filled with thick fogs.  We live plunged in abysses of air, as fishes do in abysses of water.  As the water, if it were subtilised, would become a kind of air, which would occasion the death of fishes, so the air would deprive us of breath if it should become more humid and thicker.  In such a case we should drown in the waves of that thickened air, just as a terrestrial animal drowns in the sea.  Who is it that has so nicely purified that air we breathe?  If it were thicker it would stifle us; and if it were too subtle it would want that softness which continually feeds the vitals of man.  We should be sensible everywhere of what we experience on the top of the highest mountains, where the air is so thin that it yields no sufficient moisture and nourishment for the lungs.  But what invisible power raises and lays so suddenly the storms of that great fluid body, of which those of the sea are only consequences?  From what treasury come forth the winds that purify the air, cool scorching heats, temper the sharpness of winter, and in an instant change the whole face of heaven?  On the wings of those winds the clouds fly from one end of the horizon to the other.  It is known that certain winds blow in certain seas, at some stated seasons.  They continue a fixed time, and others succeed them, as it were on purpose, to render navigation both commodious and regular: so that if men are but as patient, and as punctual as the winds, they may, with ease, perform the longest voyages.