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absorb agriculture atmosphere average barley bottom bushels capillary water carbonic acid cent clay Columella conservation of energy Deanston defects depth diminished discharge distance ditch drain-gauges drainage and evaporation drainage water drained soil draining scoop draining spade drouth earth estimated excavation experiments fall farm crops farm drainage farmers fiber crops field gauge Gisborne growing crops growth heat hygroscopic improved inches increased joints July laid land laying the tiles laying tiles less lupines measuring rod methods microbes moisture months nitrification nitrogen nutrition obstruction obtained one-half outlet percolate pipe tiles plant food porosity potential energy pots practical processes quartz quartz sand quicksand rain rainfall readily retentive soils roots of plants Rothamsted season secure shears silt six inches soil metabolism summer supply system of draining temperature three feet tile drains tillage tion tons per acre trench water surface water table wheat
Página 32 - And remember, this is not poetry, but rigid mechanical truth. He rears, as I have said, the whole vegetable world, and through it the animal ; the lilies of the field are his workmanship, the verdure of the meadows, and the cattle upon a thousand hills. He forms the muscle, he urges the blood, he builds the brain. His fleetness is in the lion's foot ; he springs in the panther, he soars in the eagle, he slides in the snake. He builds the forest and hews it down, the power which raised the tree, and...
Página 33 - The natural philosopher of to-day may dwell amid conceptions, which beggar those of Milton. So great and grand are they, that in the contemplation of them, a certain force of character is requisite to preserve us from bewilderment.
Página 68 - The removal, for a single summer night, of the aqueous vapour from the atmosphere which covers England, would be attended by the destruction of every plant which a freezing temperature could kill. In Sahara, where 'the soil is fire and the wind is flame, ' the refrigeration at night is often painful to bear.
Página 34 - ... gain nor loss. This law generalizes the aphorism of Solomon, that there is nothing new under the sun, by teaching us to detect everywhere, under its infinite variety of appearances, the same primeval force. To nature nothing can be added ; from nature nothing can be taken away...
Página 68 - Compared with the great body of the air, the aqueous vapor it contains is of almost infinitesimal amount, 99£ out of every 100 parts of the atmosphere being composed of oxygen and nitrogen. In the absence of experiment, we should never think of ascribing to this scant and varying constituent any important influence on terrestrial radiation; and yet its influence is far more potent than that of the great body of the air. To say that on a day of average humidity in England, the atmospheric vapor exerts...
Página 33 - Presented rightly to the mind, the discoveries and generalizations of modern science constitute a poem more sublime than has ever yet been addressed to the intellect and imagination of man. The natural philosopher of to-day may dwell amid conceptions, which beggar those of Milton.
Página 34 - A.nd still, notwith standing this enormous drain, in the lapse of human history we are unable to detect a diminution of his store. Measured by our largest terrestrial standards, such a reservoir of power is infinite; but it is our privilege to rise above these standards, and to regard the sun himself as a speck in infinite extension, a mere drop in the universal sea. We analyze the space in which he is immersed, and which is the vehicle of his power.