The Earth's Bounty

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Macmillan Company, 1909 - 430 páginas

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Página 308 - These are the medullary rays, which make the silver grain in quartered oak and other woods. They exist in all kinds of trees, but in many — as, for example, in the Chestnut and in most conifers — they are so fine as hardly to be seen with the naked eye. Seasoning cracks which run across the rings of growth always follow the lines of these rays, while others most often follow along some annual ring. 173 •"" rC FIG. 9. — Wood of a spruce, greatly magnified. c ANNUAL RINGS. It is correct to...
Página 308 - ... each side that it is not hard to detect them. Very often they do not extend entirely around the tree, as a true ring always does if the tree is sound. Whenever the growth of the tree is interrupted and begins again during the same season, such a false ring is formed. This happens when the foliage is destroyed by caterpillars and grows again in the same season, or when a very severe drought in early summer stops growth for a time, after late frosts, and in similar cases. HEARTWOOD AND SAPWOOD....
Página 309 - ... covered in time by other younger layers. A nail driven into a tree 6 feet from the ground will still be at the same height after it is buried under 20 or 50 or 100 layers of annual growth. But in most trees, like the Oaks and Pines, the wood becomes darker in color and harder after it has been in the tree for some years. The openings of its cells become choked so that the sap can no longer run through them.
Página 306 - ... 20.) Thus the summer wood in each year's growth is heavier, stronger, and darker in color than the spring wood. In the wood of many broadleaf trees, such as Oak and Chestnut, the spring wood is also marked by a band of open tubes of larger size called ducts. In others, such as Maple and Beech, WOOD OF THE WHITE PINE.
Página 288 - There is also a second or other variety of Angora or shawl- wool goat, besides those, generally described. This goat has an unchanging outer cover of long coarse hair, between the roots of which comes in winter an under-coat of downy wool that is naturally thrown oif in spring or is carefully combed out for use. A remarkably fine species of this breed exists throughout the area to which the white-haired goat is limited.
Página 237 - ... 6, 1902, had eaten a thousand ragweed akenes; another, killed the previous November in the same place, had eaten an equal number of the seeds of crabgrass, a troublesome weed in truck land. Birds have been shot in Mecklenburg County, Va., whose stomachs contained 3,000 leguminous seeds, mostly of tick trefoil and various species of bush clover. Pigeon grass, which is extremely common and mischievous in truck land, is a favorite food. No less than 5,000 seeds of this troublesome plant were found...
Página 237 - ... miscellaneous insects, 0.48 per cent ; the other invertebrates, largely spiders, 1.81 per cent. The vegetable food consists of grain, 23.64 per cent of the total food ; various seeds, chiefly those of weeds, 50.78 per cent ; fruit, 8.53 per cent ; miscellaneous vegetable matter, 2.12 per cent. " The Bob-white is pre-eminently a seed eater. Of its food for the year, as a whole, seeds form 50.78 per cent, and include those of many different plants. " The bulk of this seed diet consists of the seeds...

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