The poets, more perhaps than the scientists, have illustrated and held by the great law of alternation, of ebb and flow, of turn and return, in nature. An equilibrium, or, what is the same thing, a straight line, Nature abhors more than she does a vacuum. If the moisture of the air were uniform, or the heat uniform, that is, _in equilibrio,_ how could it rain? what would turn the scale? But these things are heaped up, are in waves. There is always a preponderance one way or the other; always “a steep inequality.” Down this incline the rain comes, and up the other side it goes. The high barometer travels like the crest of a sea, and the low barometer like the trough. When the scale kicks the beam in one place, it is correspondingly depressed in some other. When the east is burning up, the west is generally drowning out. The weather, we say, is always in extremes; it never rains but it pours: but this is only the abuse of a law on the part of the elements which is at the bottom of all the life and motion on the globe. The rain itself comes in shorter or longer waves,—now fast, now slow—and sometimes in regular throbs or pulse-beats. The fall and winter rains are, as a rule, the most deliberate and general, but the spring and summer rains are always more or less impulsive and capricious. One may see the rain stalking across the hills or coming up the valley in single file, as it were. Another time it moves in vast masses or solid columns, with broad open spaces between. I have seen a spring snowstorm lasting nearly all day that swept down in rapid intermittent sheets or gusts. The waves or pulsations of the storm were nearly vertical and were very marked. But the great fact about the rain is that it is the most beneficent of all the operations of nature; more immediately than sunlight even, it means life and growth. Moisture is the Eve of the physical world, the soft teeming principle given to wife to Adam or heat, and the mother of all that lives. Sunshine abounds everywhere, but only where the rain or dew follows is there life. The earth had the sun long before it had the humid cloud, and will doubtless continue to have it after the last drop of moisture has perished or been dissipated. The moon has sunshine enough, but no rain; hence it is a dead world—a lifeless cinder. It is doubtless true that certain of the planets, as Saturn and Jupiter, have not yet reached the condition of the cooling and ameliorating rains, while in Mars vapor appears to be precipitated only in the form of snow; he is probably past the period of the summer shower. There are clouds and vapors in the sun itself,—clouds of flaming hydrogen and metallic vapors, and a rain every drop of which is a burning or molten meteor. Our earth itself has doubtless passed through the period of the fiery and consuming rains. Mr. Proctor thinks there may have been a time when its showers were downpourings of “muriatic, nitric, and sulphuric acid, not