Page:The life of Matthew Flinders.djvu/528

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from the barometer. The importance of these observations was at once recognised by men connected with navigation. As the Edinburgh Review wrote, dealing with Flinders' paper when presented before the Royal Society on March 27th, 1806:[1] "It is very easy for us, speculating in our closet upon the theory of winds and their connection with the temperature, to talk of drawing a general inference on this subject with confidence. But when the philosopher chances to be a seaman on a very dangerous coast, it will be admitted that the strength of this confidence is put to a test somewhat more severe; and we find nevertheless that Captain Flinders staked the safety of his ship and the existence of himself and his crew on the truth of the above proposition." Nowadays, indeed, the principal use of a barometer to a navigator aboard ship is to enable him to anticipate changes of wind.

Not less important were his experiments and writings upon variations of the compass aboard ship. The fact that the needle of a compass showed deviations on being moved from one part of a ship to another had been observed by navigators in the eighteenth century, but Flinders was the first to experiment systematically to ascertain the cause and to invent a remedy.[2]

He observed not only that the direction of the needle varied according to the part of the ship where it was placed, but also that a change in the direction of the ship's head made a difference. Further, he found that in northern latitudes (in the English Channel, for in-

  1. Edinburgh Review, January, 1807; Flinders' Paper, "Observations on the Marine Barometer," was published in the Philosophical Transactions of the Royal Society, Part 2 1806.
  2. For the history of the matter see Alexander Smith's Introduction to W. Scoresby's Journal of a Voyage to Australia for Magnetic Research, 1859.