Edison the wages due him at the time he thus withdrew from its service, but the claim has never been pressed. The same winter of 1863-64, while at Port Huron, Edison had a further opportunity of displaying his ingenuity. An ice-jam had broken the light telegraph cable laid in the bed of the river across to Sarnia, and thus communication was interrupted. The river is three-quarters of a mile wide, and could not be crossed on foot; nor could the cable be repaired. Edison at once suggested using the steam whistle of the locomotive, and by manipulating the valve conversed the short and long outbursts of shrill sound into the Morse code. An operator on the Sarnia shore was quick enough to catch the significance of the strange whistling, and messages were thus sent in wireless fashion across the ice-floes in the river. It is said that such signals were also interchanged by military telegraphers during the war, and possibly Edison may have heard of the practice; but be that as it may, he certainly showed ingenuity and resource in applying such a method to meet the necessity. It is interesting to note that at this point the Grand Trunk now has its St. Clair tunnel, through which the trains are hauled under the river-bed by electric locomotives. Edison had now begun unconsciously the roaming and drifting that took him during the next five years all over the Middle States, and that might well have wrecked the career of any one less persistent and industrious. It was a period of his life corresponding to the Wanderjahre of the German artisan, and was an easy way of gratifying a taste for travel without the risk of privation. To-day there is little temptation to the telegrapher to go to distant parts of the country on the chance that he may secure a livelihood at the key. The ranks are well filled everywhere, and of late years the telegraph as an art or industry has shown relatively slight expansion, owing chiefly to the development of telephony. Hence, if vacancies occur, there are plenty of operators available, and salaries have remained so low as to lead to one or two formidable and costly strikes that unfortunately took no account of the economic conditions of demand and supply. But in the days of the Civil War there was a great dearth of skilful manipulators of the key. About fifteen hundred of the best operators in the country were at the front on the Federal side alone, and several hundred more had enlisted. This created a serious scarcity, and a nomadic operator going to any telegraphic centre would be sure to find a place open waiting for him. At the close of the war a majority of those who had been with the two opposed armies remained at the key under more peaceful surroundings, but the rapid development of the commercial and railroad systems fostered a new demand, and then for a time it seemed almost impossible to train new operators fast enough. In a few years, however, the telephone sprang