For security, therefore, and simplicity of definition of light, you will find no possibility of advancing beyond Plato’s “the power that through the eye manifests colour,” but on that definition, you will find, alike by Plato and all great subsequent thinkers, a moral Science of Light founded, far and away more important to you than all the physical laws ever learned by vitreous revelation. Concerning which I will refer you to the sixth lecture which I gave at Oxford in 1872,

Returning now to our subject at the point from which I permitted myself, I trust not without your pardon, to diverge; you may incidentally, but carefully, observe, that the effect of such a sky as that represented in the second diagram, so far as it can be abstracted or conveyed by painting at all, implies the total absence of any pervading warmth of tint, such as artists usually call “tone.” Every tint must be the purest possible, and above all the white. Partly, lest you sh

These three instances are all I have time to give of the former conditions of serene weather, and of non-electric rain-cloud. But I must yet, to complete the sequence of my subject, show you one example of a good, old-fashioned, healthy, and mighty, storm. In Diagram 4, Mr. Severn has beautifully enlarged my sketch of a July thunder-cloud of the year 1858, on the Alps of the Val d’Aosta, seen from Turin, that is to say, some twenty-five or thirty miles distant. You see that

We so rarely now see cumulus cloud of this grand kind, that I will yet delay you by reading the description of its nearer aspect, in the 130th page of Eagle’s Nest : 1— “The rain which flooded our fields the Sunday before last, was followed, as you will remember, by bright days, of which Tuesday the 20th (February, 1872) was, in London, notable for the splendour, towards the afternoon, of its white cumulus clouds. There has been so much black east wind lately, and so much f

Thus far then of clouds that were once familiar; now at last, entering on my immediate subject, I shall best introduce it to you by reading an entry in my diary which gives progressive description of the most gentle aspect of the modern plague-cloud. “BOLTON ABBEY, 4 th July , 1875. “Half-past eight, morning; the first bright morning for the last fortnight.“At half-past five it was entirely clear, and entirely calm; the moorlands glowing, and the Wharfe glittering in sacred l

The first time I recognized the clouds brought by the plague-wind as distinct in character was in walking back from Oxford, after a hard day’s work, to Abingdon, in the early spring of 1871: it would take too long to give you any account this evening of the particulars which drew my attention to them; but during the following months I had too frequent opportunities of verifying my first thoughts of them, and on the first of July in that year wrote the description of them whic

Since that Midsummer day, my attention, however otherwise occupied, has never relaxed in its record of the phenomena characteristic of the plague-wind; and I now define for you, as briefly as possible, the essential signs of it. (1.) It is a wind of darkness,—all the former conditions of tormenting winds, whether from the north or east, were more or less capable of co-existing with sunlight, and often with steady and bright sunlight; but whenever, and wherever the plague-win

(2.) It is a malignant quality of wind, unconnected with any one quarter of the compass; it blows indifferently from all, attaching its own bitterness and malice to the worst characters of the proper winds of each quarter. It will blow either with drenching rain, or dry rage, from the south,—with ruinous blasts from the west,—with bitterest chills from the north,—and with venomous blight from the east. Its own favourite quarter, however, is the south-west, so that it is dist

(3.) It always blows tremulously , making the leaves of the trees shudder as if they were all aspens, but with a peculiar fitfulness which gives them—and I watch them this moment as I write—an expression of anger as well as of fear and distress. You may see the kind of quivering, and hear the ominous whimpering, in the gusts that precede a great thunderstorm; but plague-wind is more panic-struck, and feverish; and its sound is a hiss instead of a wail. When I was last at Ava

(4.) Not only tremulous at every moment, it is also intermittent with a rapidity quite unexampled in former weather. There are, indeed, days—and weeks, on which it blows without cessation, and is as inevitable as the Gulf Stream; but also there are days when it is contending with healthy weather, and on such days it will remit for half an hour, and the sun will begin to show itself, and then the wind will come back and cover the whole sky with clouds in ten minutes; and so on

(5.) It degrades, while it intensifies, ordinary storm; but before I read you any description of its efforts in this kind, I must correct an impression which has got abroad through the papers,1 that I speak as if the plague-wind blew now always, and there were no more any natural weather. On the contrary, the winter of 1878–9 was one of the most healthy and lovely I ever saw ice in;—Coniston lake shone under the calm clear frost in one marble field, as strong as the floor of

These extracts are, I hope, enough to guard you against the absurdity of supposing that it all only means that I am myself soured, or doting, in my old age, and always in an ill humour. Depend upon it, when old men are worth anything, they are better-humoured than young ones; and have learned to see what good there is, and pleasantness, in the world they are likely so soon to have orders to quit. Now then—take the following sequences of accurate description of thunderstorm,

(6.) And now I come to the most important sign of the plague-wind and the plague-cloud: that in bringing on their peculiar darkness, they blanch the sun instead of reddening it. And here I must note briefly to you the uselessness of observation by instruments, or machines, instead of eyes. In the first year when I had begun to notice the specialty of the plague-wind, I went of course to the Oxford observatory to consult its registrars. They have their anemometer always on the

Now I’m going to show you a diagram of a sunset in entirely pure weather, above London smoke. I saw it and sketched it from my old post of observation—the top garret of my father’s house at Herne Hill. There, when the wind is south, we are outside of the smoke and above it; and this diagram,1 admirably enlarged from my own drawing by my, now in all things best aide-de-camp, Mr. Collingwood, shows you an old-fashioned sunset—the sort of thing Turner and I used to have to look

I should have liked to have blotted down for you a bit of plague-cloud to put beside this; but Heaven knows, you can see enough of it nowadays without any trouble of mine; and if you want, in a hurry, to see what the sun looks like through it, you’ve only to throw a bad half-crown into a basin of soap and water. Blanched Sun,—blighted grass,—blinded man.—If, in conclusion, you ask me for any conceivable cause or meaning of these things—I can tell you none, according to your

What is best to be done, do you ask me? The answer is plain. Whether you can affect the signs of the sky or not, you can the signs of the times. Whether you can bring the sun back or not, you can assuredly bring back your own cheerfulness, and your own honesty. You may not be able to say to the winds, “Peace; be still,” but you can cease from the insolence of your own lips, and the troubling of your own passions. And all that it would be extremely well to do, even though the