| “Out of Bristowe, and costes many one, Men haue practised by nedle and by stone Thider wardes within a litle while.” Hakluyt, Principal Navigations, p. 201 (London, 1599). |
From this it would seem that the compasses used at that time by English mariners were of a very primitive description. Barlowe, in his treatise Magnetical Advertisements, printed in 1616 (p. 66), complains that “the Compasse needle, being the most admirable and usefull instrument of the whole world, is both amongst ours and other nations for the most part, so bungerly and absurdly contrived, as nothing more.” The form he recommends for the needle is that of “a true circle, having his Axis going out beyond the circle, at each end narrow and narrower, unto a reasonable sharpe point, and being pure steele as the circle it selfe is, having in the middest a convenient receptacle to place the capitell in.” In 1750 Dr Gowan Knight found that the needles of merchant-ships were made of two pieces of steel bent in the middle and united in the shape of a rhombus, and proposed to substitute straight steel bars of small breadth, suspended edgewise and hardened throughout. He also showed that the Chinese mode of suspending the needle conduces most to sensibility. In 1820 Peter Barlow reported to the Admiralty that half the compasses in the British Navy were mere lumber and ought to be destroyed. He introduced a pattern having four or five parallel straight strips of magnetized steel fixed under a card, a form which remained the standard admiralty type until the introduction of the modern Thomson (Kelvin) compass in 1876.
(F. H. B.; S. P. T.)
[1] Adamas in India reperitur ... Ferrum occulta quadam natura ad se trahit. Acus ferrea postquam adamantem contigerit, ad stellam septentrionalem ... semper convertitur, unde valde necessarius est navigantibus in mari.
[2] Sicut acus per naturam vertitur ad septentrionem dum sit tacta a magnete.—Sicut acus nautica dirigit marinarios in sua navigatione.
[3] Ginguené, Hist. lit. de l’Italie, t. i. p. 413.
[4] “According to all the texts he returned to Venice in 1295 or, as is more probable, in 1296.”—Yule.
COMPASS PLANT, a native of the North American prairies, which takes its name from the position assumed by the leaves. These turn their edges to north and south, thus avoiding the excessive mid-day heat, while getting the full benefit of the morning and evening rays. The plant is known botanically as Silphium laciniatum, and belongs to the natural order Compositae. Another member of the same order, Lactuca Scariola, which has been regarded as the origin of the cultivated lettuce (L. sativa), behaves in the same way when growing in dry exposed places; it is a native of Europe and northern Asia which has got introduced into North America.