THE SUN.
Although, as mentioned last month, the sun gives out such a vast amount of heat and light, we must remember that these are sent out in all directions, and that we receive comparatively a very small portion. The best estimates make our part one twenty-three-hundred-millionths of the whole. But this quantity is no trifling matter, and its effects are not to be overlooked. Speaking of the general effect of the sun’s influence, Prof. Lockyer puts it in this way: “The enormous engines which do the heavy work of the world—the locomotives which take us so smoothly and rapidly across a whole continent—the mail packets which bear us so safely over the broad ocean—owe all their power to steam; and steam is produced by heating water by coal. We all know that coal is the product of an ancient vegetation; and vegetation is the direct effect of the sun’s action. Hence without the sun’s action in former times, we should have had no coal. The heavy work of the world is, therefore, indirectly done by the sun. Now for the light work. Let us take man. To work, a man must eat; does he eat beef? On what was the animal which supplied the beef fed? On grass. Does he eat bread? Of what is bread made? Of the flour of wheat and other grains. In these, and in all cases, we come back to vegetation, which is the direct effect of the sun’s action. Here again, then, we must confess that to the sun is due man’s power of work. In fact, all the world’s work, with the trifling exception of tide-work, is done by the sun; and man himself, prince or peasant, is but a little engine, which merely directs the energy supplied by the sun.” The use of the sun as a time-piece is perhaps more frequently thought of than any other, since its value is constantly presenting itself. Each day, as noon approaches, the question occurs, “How is the time?” and when possible, the time of crossing the meridian is compared with that exhibited by the clock. For this month, on the 1st, noon by the sun occurs at 11:57 a. m. clock time; on the 15th, at 11:56 a. m.; on the 31st, at 11:57½ a. m. Another method, though not very accurate, of determining time, is the noting of the rising and setting of the sun. One difficulty here would be the obtaining of a good horizon, such for example, as could be had at sea. The following times answer very well for most parts of the United States and Canada: On the 1st sun rises at 5:02 a. m. and sets at 6:52 p. m.; daybreak occurs at 4:08 a. m., and twilight ends at 8:46 p. m.; on the 15th, sun rises at 4:48 a. m., sets at 7:05 p. m.; daybreak at 2:44 a. m., and end of twilight at 9:09 p. m.; and on the 31st, sun rises at 4:37 a. m., and sets at 7:17 p. m.; daybreak occurs 2:24 a. m., and twilight ends 9:30 p. m. During the month the days increase in length some fifty minutes. On the 31st the sun reaches its highest elevation above the horizon, which in latitude 41° 30′ north is 70° 33′, nearly. As we are now moving away from the sun, its apparent diameter diminishes from 31′ 48″ to 31′ 37″.