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Level Fall: If the population in the higher level fall is the greater, the signal will cause some of the electrons at the higher level fall to fall to the lower level fall, the energy released in the process increasing that of the signal. Normally the lowest energy level fall has the largest population, and successively higher energy level falls have progressively smaller populations. Thus the crystal ordinarily absorbs energy. If the normal distribution is reversed, however, amplification may be obtained. The most practical way of accomplishing this is as follows:
Make certain that the tops of each pair of stakes are perfectly level fall.
If you use a line level fall, the pairs of stakes may be 20 feet apart. On top of the stake that should be lowest place a block of a thickness equal to the difference in heights between successive pairs of stakes (one and two tenths inches if the fall is to be six inches per 100 feet). Stretch a thin line •with line level fall hooked at about its center between the top of the block and the top of a stake of the next pair farther up the line. Read the level fall. It should indicate that the top of the block and the top of the stake are level fall. If it does not, adjust the upper pair of stakes until they are level fall.
But each successive pair must be slightly higher than the pair before. The amount of this rise must be the same as the amount of fall the drain is to have. To illustrate: suppose you have decided upon a fall of six inches in every 100 feet. That is equivalent to six tenths of an inch every 10 feet or one and two tenths inches every 20 feet. If your stakes are 10 feet apart, each successive pair must be six tenths of an inch higher than last pair; if 20 feet apart, one-and-two-tenths inches higher.
You may establish the correct height of successive pairs of stakes in various ways:with a surveyor's level fall or a transit if one is available, with a straightedge and level fall, or with a line level fall. There are other methods. The important thing is that the measurements be accurate. |
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