Smith Compared with Arkwright.

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vance which was almost tantamount to a new invention. It was impossible to overrate the advantages which this and other countries had derived from his untiring and devoted patience in prosecuting the invention to a successful issue." Baron Charles Dupin compared the farmer Smith with the barber Arkwright: "He had the same perseverance and the same indomitable courage. These two moral qualities enabled him to triumph over every obstacle." This was the great merit of "Screw" Smith-that he was determined to realize what his predecessors had dreamed of achieving; and he eventually accomplished his great purpose.

CHAPTER III.

JOHN HARRISON,

INVENTOR OF THE MARINE CHRONOMETER.*

"No man knows who invented the mariner's compass, or who first hollowed out a canoe from a log. The power to observe accurately the sun, moon, and planets, so as to fix a vessel's actual position when far out of sight of land, enabling long voyages to be safely made; the marvellous improvements in ship-building, which shortened passages by sailing vessels, and vastly reduced freights even before steam gave an independent force to the carrier-each and all were done by small advances, which together contributed to the general movement of mankind. Each owes all to the others. The forgotten inventors live forever in the usefulness of the work they have done and the progress they have striven for."-H. M. HYND

MAN.

...

ONE of the most extraordinary things connected with applied science is the method by which the navigator is enabled to find the exact spot of sea on which his ship rides. There may be nothing but water and sky within his view; he may be in the midst of the ocean, or gradually nearing the land; the curvature of the globe baffles the search of his telescope; but if he have a correct chronometer, and can make an astronomical observation, he may readily ascertain his longitude, and know his approximate position-how far he is from home, as well as from his intended destination. He is even enabled, at some special place, to

*Originally published in Longman's Magazine, but now rewritten and enlarged.

Use of Practical Astronomy.

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send down his grappling-irons into the sea, and pick up an electrical cable for examination and repair.

This is the result of a knowledge of practical astronomy. "Place an astronomer," says Mr. Newcomb, "on board a ship; blindfold him; carry him by any route to any ocean on the globe, whether under the tropics or in one of the frigid zones; land him on the wildest rock that can be found; remove his bandage, and give him a chronometer regulated to Greenwich or Washington time, a transit instrument with the proper appliances, and the necessary books and tables, and in a single clear night he can tell his position within a hundred yards by observations of the stars. This, from a utilitarian point of view, is one of the most important operations of pràctical astronomy."

The marine chronometer was the outcome of the crying want of the sixteenth century for an instrument that should assist the navigator to find his longitude on the pathless ocean. Spain was then the principal naval power; she was the most potent monarchy in Europe, and held half America under her sway. Philip III. offered 100,000 crowns for any discovery by means of which the longitude might be determined by a better method than by the log, which was found very defective. Holland next became a great naval power, and followed the example of Spain in offering 30,000 florins for a similar discovery. But, though some efforts were made, nothing practical was done, principally through the defective state of astronomical instruments. England succeeded Spain and Holland as a naval power; and when Charles II. established the Greenwich Observatory, it was made a special point that Flamsteed, the astronomer-royal, should direct his

* "Popular Astronomy." By Simon Newcomb, LL.D., Professor U. S. Naval Observatory.

best energies to the perfecting of a method for finding the longitude by astronomical observations. But though Flamsteed, together with Hallay and Newton, made some progress, they were prevented from obtaining ultimate success by the want of efficient chronometers and the defective nature of astronomical instruments.

Nothing was done until the reign of Queen Anne, when a petition was presented to the Legislature on the 25th of May, 1714, by "several captains of her majesty's ships, merchants in London, and commanders of merchantmen, in behalf of themselves, and of all others concerned in the navigation of Great Britain," setting forth the importance of the accurate discovery of the longitude, and the inconvenience and danger to which ships were subjected from the want of some suitable method of discovering it. The petition was referred to a committee, which took evidence on the subject. It appears that Sir Isaac Newton, with his extraordinary sagacity, hit the mark in his report. "One is," he said, "by a watch to keep time exactly; but, by reason of the motion of a ship, and the variation of heat and cold, wet and dry, and the difference of gravity in different latitudes, such a watch hath not yet been made."

An act was, however, passed in the session of 1714, offering a very large public reward to inventors: £10,000 to any one who should discover a method of determining the longitude to one degree of a great circle, or sixty geographical miles; £15,000 if it determined the same to two thirds of that distance, or forty geographical miles; and £20,000 if it determined the same to one half of the same distance, or thirty geographical miles. Commissioners were appointed by the same act, who were instructed that one moiety or half part of such reward shall be due and paid when

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Experiments in Watchmaking.

75

the said commissioners, or the major part of them, do agree that any such method extends to the security of ships within eighty geographical miles of the shore, which are places of the greatest danger; and the other moiety or half part when a ship, by the appointment of the said commissioners, or the major part of them, shall actually sail over the ocean from Great Britain to any such port in the West Indies as those commissioners, or the major part of them, shall choose or nominate for the experiment, without losing the longitude beyond the limits before mentioned."

The terms of this offer indicate how great must have been the risk and inconvenience which it was desired to remedy. Indeed, it is almost inconceivable that a reward so great could be held out for a method which would merely afford security within eighty geographical miles!

This splendid reward for a method of discovering the longitude was offered to the world-to inventors and scientific men of all countries-without restriction of race, or nation, or language. As might naturally be expected, the prospect of obtaining it stimulated many ingenious men to make suggestions and contrive experiments; but for many years the successful construction of a marine time-keeper seemed almost hopeless. At length, to the surprise of every one, the prize was won by a village carpenter-a person of no school, or university, or college whatever.

Even so distinguished an artist and philosopher as Sir Christopher Wren was engaged, as late in his life as the year 1720, in attempting to solve this important problem. As has been observed, in the memoir of him. contained in the "Biographia Britannica,"*"This no

*"Biographia Britannica," vol. vi. part 2, p. 4375. This volume was published in 1766, before the final reward had been granted to Harrison.