Thus the idea of the screw propeller to be worked by his own improved engine was propounded by Watt one hundred and thirty-five years ago.
This is a remarkable letter, and a still more remarkable sketch, and adds another to the many true forecasts of future development made by this teeming brain.
Watt also made a survey of the Clyde, and reported upon its proposed deepening. His suggestions remained unacted upon for several years, when the work was begun, and is not ended even in our day, of making a trout and salmon stream into one of the busiest, navigable highways of the world. This year further improvements have been decided upon, so that the monsters of our day, with 16,000-horse-power turbine engines, may be built near Glasgow. Watt also made surveys for a canal between Perth and Coupar Angus, for the well-known Crinan Canal and other projects in the Western Highlands, as also for the great Caledonian and the Forth and Clyde Canals.
The Perth Canal was forty miles long through a rough country, and took forty-three days, for which Watt's fee, including expenses, was $400. Labor, even of the highest kind, was cheap in those times. We note his getting thirty-seven dollars for plans of a bridge over the Clyde. Watt prepared plans for docks and piers at Port Glasgow and for a new harbor at Ayr. His last and most important engineering work in Scotland was the survey of the Caledonian Canal, made in the autumn of 1773, through a district then without roads. "An incessant rain kept me," he writes, "for three days as wet as water could make me. I could scarcely preserve my journal book."
Suffice it to note that he saved enough money to be able to write, "Supposing the engine to stand good for itself, I am able to pay all my debts and some little thing more, so that I hope in time to be on a par with the world."
We are now to make one of the saddest announcements saving dishonor that it falls to man to make. Watt's wife died in childbed in his absence. He was called home from surveying the Caledonian Canal. Upon arrival, he stands paralysed for a time at the door, unable to summon strength to enter the ruined home. At last the door opens and closes and we close our eyes upon the scene—no words here that would not be an offence. The rest is silence.
Watt tried to play the man, but he would have been less than man if the ruin of his home had not made him a changed man. The recovery of mental equipoise proved for a time quite beyond his power. He could do all that man could do, "who could do more is none." The light of his life had gone out.