"But easily explained, in so far as how it acts, but not why it performs its work," Mr. Doane answered. "The needle which you see has a mate, and that mate is in the California office. These needles are made in pairs, and, by a wonderful process, made sympathetic. No two pairs are charged with the same sympathy; consequently, no other needle of the whole system of instruments will affect this save that single one in California. The instruments of each pair are most carefully set up at their different stations, so that the needles shall point to the true north; thus the needles are exactly parallel to each other. When the instrument is not in use, the key is left open, and the needle is held back by its spring. Now, if the California operator should close his key, he would cause his needle to be attracted toward the relay magnets; this movement of his needle exerts a sympathetic influence upon the needle in this instrument. _It endeavors to parallel itself to its mate._ It moves to the right, overcoming the power of its spring, and, touching the stud, closes the circuit, and the sounder records the fact. Opening his key in California, both needles move back by the tension of their springs, and the sounders are demagnetized. The sympathy of these two needles to place themselves in a parallel position, or, more properly, the repulsion of the poles of each from those of the other, is the secret of the sympathetic telegraph system." "A wonderful, grand invention!" burst from the lips of Cobb, as he comprehended the almost human action of the two needles. "How could mortal man have discovered such a secret of nature!" "Yes, Junius; it is wonderful!" echoed Hugh. "How many pairs of these sagacious little instruments have you in the system?" asked Cobb, after a silence. "In the United States, 280,000; in the world, 450,000. But more are needed very much, and have been for years," returned Mr. Doane. "Well, why don't you make them?" inquiringly. "Ah! there's where the trouble is! Since 1963 no instruments have been made. The secret is lost!" "Lost! The secret is lost! How could it be possible to lose the secret of such a discovery as this?" and a look of incredulity expressed the doubts he entertained. "It is a fact, nevertheless, Mr. Cobb; a fact coupled with sorrow to me in many ways. But let us take the drag and return to the house, as it is near luncheon; I will tell you of the accident as we ride along." A shade of sorrow came over his face as he spoke. As the drag sped along the grand avenue toward the beautiful home of the superintendent, Cobb listened to the old man's story concerning the loss of the secret of Jean Colchis' great invention. "My grandfather," commenced Mr. Doane, "was the first superintendent of the sympathetic telegraph system. In 1892, when the wonderful discovery of Jean Colchis, of whom you no doubt have heard--"