established the Greenwich Observatory, it was made a special point that Flamsteed, the Astronomer-Royal, should direct his best energies to the perfecting of a method for finding the longitude by astronomical observations.

But though Flamsteed, together with Halley 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: 10,000L.