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. If we assume that all steam engines work an average of only eight hours in the twenty-four, as men and horses do (those on duty longer hours are not under continuous exertion), it still follows that the 150,000,000 of effective steam-power, each doing the work of twelve men, equals the work of 1,800,000,000 of men, or of 150,000,000 of horses. Engel estimated that in 1880 the value of world industries dependent upon steam was thirty-two thousand millions of dollars, and that in 1888 it had reached forty-three thousand millions of dollars. It is to-day doubtless more than sixty thousand millions of dollars, a great increase no doubt over 1880, but the one figure is as astounding as the other, for both mean nothing that can be grasped. The chief steam-using countries are America, 14,400,000 horse-power in 1888; Britain, 9,200,000 horse-power nominal. If we add the British colonies and dependencies, 7,120,000 horse-power, the English-speaking race had three-fifths of all the steam-power of the world.