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Basics of electricity. Principles of electromagnetism. Distribution of electricity. Electric motors. Lighting. Environmental control. Principles of electronics. Controls.
Excerpt from Electricity in Agriculture and Horticulture The cause of the astonishing development of vegetation under such conditions has hitherto been held to lie in the long day, which lasts from two to three months in these regions during their short summer. It is further sometimes supposed that this circumstance will provide the crops with more light and heat, the principal factors of vegetation. This is, however, not true, for calculation shows that the quantity, notwithstanding this long day, is less than it is, for instance, in 60 deg. Of latitude. In consequence of the low height of the sun over the horizon, the rays meet the earth in such an oblique direction that their illuminating...