I must acknowledge that at present I can produce no older information in regard to vanes used on board ship, to indicate the course of the wind, than of the eleventh century, taken from the life of Emma, the consort of Canute the Great, king of Denmark, Norway and England, the author of which was an eye-witness of what he relates. Describing the magnificent Norman fleet sent to England in the year 1013, he says that birds, which turned round with the wind, were placed on the top of the masts[686].
At that time, therefore, instead of the flags used at present, a vane, shaped like a bird, was placed at the summit of the mast; perhaps also the figure of a cock, as the emblem of vigilance, but in this case not of clerical vigilance. In the cathedral of Bayeux, in France, is a piece of tapestry, representing the actions of William the Conqueror, executed with the needle, either by his consort or under her direction, in which vanes are seen at the top of the masts in many of the ships[687].
[Anemoscopes, or instruments for showing the direction of the wind, are now in constant use in meteorological establishments; the indications are made upon dials, and the apparatus does not differ in principle from that described by Beckmann.
Anemometers, or instruments for measuring the power or force of the wind, have also been contrived of various kinds. The first was invented by Wolf. In this the wind acted upon four sails somewhat resembling those of a windmill, the motion being communicated by cog-wheels to a lever loaded with a weight. When the wind acted upon the sails, the bar rose, this motion continuing until the increased leverage of the weight counterpoised the moving power of the wind. Others on a different principle have been made by Lind, Regnier, Martin, and a very beautiful instrument for this purpose, constructed by Mr. Dent, may be seen at Lloyd’s room in the Royal Exchange.]
FOOTNOTES
[661] Medea, ver. 316.
[662] Odyss. v. 295.
[663] Iliad, ix. 5.
[664] Aristot. Meteorol. ii. cap. 5 et 6. On this account, as Salmasius remarks, the book De Mundo cannot belong to Aristotle, as mention is made in it of twelve winds.
[665] De Vita et Gestis Caroli Magni. Traj. 1711, 4to, pp. 132, 133.