Sycamore Plane braird also suffers by late frost, and for greater security ought also to be sown partly in March and partly in April. Planes require dry, poor, rather exposed sandy soil, for seed-bed; as, in rich damp soil, the top of the annual shoot does not ripen: the seed ought to be thinly sown. Birch and Alder seeds require to be sown in March, or beginning of April, on very fine, rich, easy mould, giving them very slight cover, especially the birch. The Coniferæ, Scots Fir, Spruce, Silver Fir, &c. should be sown in April, on very rich easy soil. The greatest care is required to deposit these different seeds at proper regular depth, from an inch to the fourth of an inch, in proportion to the size of the seed. Larch should also be sown in April; it succeeds best on the clean mellow ground which has produced a crop of seedling Scots fir. It is worthy of remark, that the larch seedlings and row-plants are liable to die under a putrescent disease, when much recent manure is employed.—We remark this accordance with its tendency to putrid disease in after life. {175} Acorns, Chestnuts, and other large seeds, may be economically sown in drill: where the soil contains much annual weed seed, this admits of expeditious cleaning by the hoe. Ground which has borne a crop of potatoes the preceding season, is unfit for seed-beds, as the tubers and seed of the potato give much trouble. These are the chief of Mr Sang’s directions on raising timber-plants. With the exception of kiln-drying of cones, and being rather too prodigal of manure to the seed-beds (perhaps necessary in a sale nursery), we see nothing in the volume to censure.—A premium should be offered for a convenient plan of distributing fir-seed suitably in the seed-bed, without the aid of artificial drying. It is perhaps unnecessary to state, that, in the culture of trees, there are thousands of incidental circumstances to which general directions will not apply, and which demand a discriminating judgment in the operator: this acts as a school to the mental acumen; and there is no class of operative men, which has the faculties of attention, activity, discrimination, and judgment, more developed, than nurserymen and gardeners,—whose diversified labours, requiring, at the same time, constant mental and corporeal exertion, keep up a proper balance of the human powers. {176}