Watt's next "hobby" fortunately became an engrossing occupation and kept him alert. This was a machine for copying sculpture. A machine he had seen in Paris for tracing and multiplying the dies of medals, suggested the other. After much labor and many experiments he did get some measure of success, and made a large head of Locke in yellow wood, and a small head of his friend Adam Smith.
Long did Watt toil at the new hobby in the garret where it had been created, but the garret proved too hot in summer and too cold in winter. March 14, 1810, he writes Berthollet and Levèque:
I still do a little in mechanics: a part of which, if I live to complete it, I shall have the honor of communicating to my friends in France.
He went steadily forward and succeeded in making some fine copies in 1814. For one of Sappho he gives dates and the hours required for various parts, making a total of thirty-nine. Some censorious Sabbatarians discovered that the day he was employed one hour "doing her breast with 1/8th drill" was Sabbath, which in one who belonged to a strict Scottish Covenanter family, betokened a sad fall from grace. When we consider that his health was then precarious, that he was debarred from chemical experiments, and depended solely upon mechanical subjects; that in all probability it was a stormy day (Sunday, February 3, 1811), knowing also that "Satan finds mischief still for idle hands to do," we hope our readers will pardon him for yielding to the irresistible temptation, even if on the holy Sabbath day for once he could not "get off" his captivating hobby.
The historical last workshop of the great worker with all its contents remains open to the public to-day just as it was when he passed away. Pilgrims from many lands visit it, as Shakespeare's birthplace, Burns' cottage, and Scott's Abbottsford attract their many thousands yearly. We recommend our readers to add to these this garret of Watt in their pilgrimages.
[1] Sinclair's "Development of the Locomotive" tends to deprive Stephenson of some part of his fame as inventor. Much importance is attached to Hedley's "Puffing Billy," 1813, which is pronounced to have been a commercial success. Sinclair, however, credits Stephenson with doing most of all men to introduce the Locomotive. As the final verdict may admit Hedley and cannot expel Stephenson from the temple of fame, we pass the sentence as written, leaving to future disputants to adjust rival claims.
CHAPTER VIII
The Record of the Steam Engine
The Soho works, up to January, 1824, had completed 1164 steam engines, of a nominal horse-power of 25,945; from January, 1824, to 1854, 441 engines, nominal horse-power, 25,278, making the total number 1605, of nominal horse-power, 51,223, and real horse-power, 167,319. Mulhall gives the total steam-power of the world as 50,150,000 horse-power in 1888. In 1880 it was only 34,150,000. Thus in eight years it increased, say, fifty per cent. Assuming the same rate of increase from 1888 to 1905, a similar period, it is to-day 75,000,000 nominal, which Engel says may be taken as one-half the effective power (vide Mulhall, "Steam," p. 546), the real horse-power in 1905 being 150,000,000. One horse-power raises ten tons a height of twelve inches per minute. Working eight hours, this is about 5,000 tons daily, or twelve times a man's work, and as the engine never tires, and can be run constantly, it follows that each horse-power it can exert equals thirty-six men's work; but, allowing for stoppages, let us say thirty men. The engines of a large ocean greyhound of 35,000 horse-power, running constantly from port to port, equal to three relays of twelve men per horse-power, is daily exerting the power of 1,260,000 men, or 105,000 horses. Assuming that all the steam engines in the world upon the average work double the hours of men, then the 150,000,000 horse-power in the world, each equal to two relays of twelve men per horse-power, exerts the power of 3,600,000,000 of men. There are only one-tenth as many male adults in the world, estimating one in five of the population.