Its earliest application was in such operations as pumping, wherein mere force is required. Soon, however, it vindicated its delicacy of touch in the industrial arts of spinning and weaving. It created vast manufacturing establishments, and supplied clothing for the world. It changed the industry of nations. In its application, first to the navigation of rivers, and then to the navigation of the ocean, it more than quadrupled the speed that had heretofore been attained. Instead of forty days being requisite for the passage, the Atlantic might now be crossed in eight. But, in land transportation, its power was most strikingly displayed. The admirable invention of the locomotive enabled men to travel farther in less than an hour than they formerly could have done in more than a day. The locomotive has not only enlarged the field of human activity, but, by diminishing space, it has increased the capabilities of human life. In the swift transportation of manufactured goods and agricultural products, it has become a most efficient incentive to human industry The perfection of ocean steam-navigation was greatly promoted by the invention of the chronometer, which rendered it possible to find with accuracy the place of a ship at sea. The great drawback on the advancement of science in the Alexandrian School was the want of an instrument for the measurement of time, and one for the measurement of temperature--the chronometer and the thermometer; indeed, the invention of the latter is essential to that of the former. Clepsydras, or water-clocks, had been tried, but they were deficient in accuracy. Of one of them, ornamented with the signs of the zodiac, and destroyed by certain primitive Christians, St. Polycarp significantly remarked, "In all these monstrous demons is seen an art hostile to God." Not until about 1680 did the chronometer begin to approach accuracy. Hooke, the contemporary of Newton, gave it the balance-wheel, with the spiral spring, and various escapements in succession were devised, such as the anchor, the dead-beat, the duplex, the remontoir. Provisions for the variation of temperature were introduced. It was brought to perfection eventually by Harrison and Arnold, in their hands becoming an accurate measure of the flight of time. To the invention of the chronometer must be added that of the reflecting sextant by Godfrey. This permitted astronomical observations to be made, notwithstanding the motion of a ship. Improvements in ocean navigation are exercising a powerful influence on the distribution of mankind. They are increasing the amount and altering the character of colonization.