One has the leisure of July for perceiving all the differences of the green of leaves. It is no longer a difference in degrees of maturity, for all the trees have darkened to their final tone, and stand in their differences of character and not of mere date. Almost all the green is grave, not sad and not dull. It has a darkened and a daily colour, in majestic but not obvious harmony with dark grey skies, and might look, to inconstant eyes, as prosaic after spring as eleven o'clock looks after the dawn. Gravity is the word--not solemnity as towards evening, nor menace as at night. The daylight trees of July are signs of common beauty, common freshness, and a mystery familiar and abiding as night and day. In childhood we all have a more exalted sense of dawn and summer sunrise than we ever fully retain or quite recover; and also a far higher sensibility for April and April evenings--a heartache for them, which in riper years is gradually and irretrievably consoled. But, on the other hand, childhood has so quickly learned to find daily things tedious, and familiar things importunate, that it has no great delight in the mere middle of the day, and feels weariness of the summer that has ceased to change visibly. The poetry of mere day and of late summer becomes perceptible to mature eyes that have long ceased to be sated, have taken leave of weariness, and cannot now find anything in nature too familiar; eyes which have, indeed, lost sight of the further awe of midsummer daybreak, and no longer see so much of the past in April twilight as they saw when they had no past; but which look freshly at the dailiness of green summer, of early afternoon, of every sky of any form that comes to pass, and of the darkened elms. Not unbeloved is this serious tree, the elm, with its leaf sitting close, unthrilled. Its stature gives it a dark gold head when it looks alone to a late sun. But if one could go by all the woods, across all the old forests that are now meadowlands set with trees, and could walk a county gathering trees of a single kind in the mind, as one walks a garden collecting flowers of a single kind in the hand, would not the harvest be a harvest of poplars? A veritable passion for poplars is a most intelligible passion. The eyes do gather them, far and near, on a whole day's journey. Not one is unperceived, even though great timber should be passed, and hill-sides dense and deep with trees. The fancy makes a poplar day of it. Immediately the country looks alive with signals; for the poplars everywhere reply to the glance. The woods may be all various, but the poplars are separate.