Twenty-five years ago I went into a camera obscura, where you see miniature men and women, coloured photographs alive and moving, trees waving, now and then dogs crossing the bright sun picture. I was only there a few moments, and I have never been in one since, and yet so inexplicable a thing is memory, the picture stands before me now clear as if it were painted and tangible. So many millions of pictures have come and gone upon the retina, and yet I can single out this one in an instant, and take it down as you would a book from a shelf. The millions of coloured etchings that have fixed themselves there in the course of those years are all in due order in the portfolio of the mind, and yet they cannot occupy the space of a pin's point. They have neither length, breadth, nor thickness, none of the qualifications of mathematical substance, and yet they must in some way be a species of matter. The fact indicates the possibility of still more subtle existences. Now I wish I could put before you a coloured, living, moving picture, like that of the camera obscura, of some other wheat-fields at a sunnier time. They were painted on the surface of a plain, set round about with a margin of green downs. They were large enough to have the charm of vague, indefinite extension, and yet all could be distinctly seen. Large squares of green corn that was absorbing its yellow from the sunlight; chess squares, irregularly placed, of brown furrows; others of rich blood-red trifolium; others of scarlet sainfoin and blue lucerne, gardens of scarlet poppies here and there. Not all of these, of course, at once, but they followed so quickly in the summer days that they seemed to be one and the same pictures, and had you painted them altogether on the same canvas, together with ripe wheat, they would not have seemed out of place. Never was such brilliant colour; it was chalk there, and on chalk the colours are always clearer, the poppies deeper, the yellow mustard and charlock a keener yellow; the air, too, is pellucid. Waggons going along the tracks; men and women hoeing; ricks of last year still among clumps of trees, where the chimneys and gables of farmhouses are partly visible; red-tiled barns away yonder; a shepherd moving his hurdles; away again the black funnel of an idle engine, and the fly-wheel above hawthorn bushes--all so distinct and close under that you might almost fear to breathe for fear of dimming the mirror. The few white clouds sailing over seemed to belong to the fields on which their shadows were now foreshortened, now lengthened, as if they were really part of the fields, like the crops, and the azure sky so low down as to be the roof of the house and not at all a separate thing. And the sun a lamp that you might almost have pushed along his course faster with your hand; a loving and interesting sun that wanted the wheat to ripen, and stayed there in the slow-drawn arc of the summer day to lend a hand. Sun and sky and clouds close here