hould call them, but far from yachtlike
in shape or nimbleness. With their length seldom more than thrice their
width of beam, with narrow tower-like poops, with broad-shouldered bows
and bowsprit weighed down with spritsail yards, and with no canvas
higher than a topsail, these clumsy caravels could make but little
progress against head-winds, and the amount of tacking and beating to
and fro was sometimes enough to quadruple the length of the voyage. For
want of metallic sheathing below the waterline the ship was liable to be
sunk by the terrible worm which, in Hakluyt's phrase, "many times
pearceth and eateth through the strongest oake." For want of vegetable
food in the larder, or anything save the driest of bread and beef
stiffened with brine, the sailors were sure to be attacked by scurvy,
and in a very long voyage the crew was deemed fortunate that did not
lose half its number from that foul disease. Often in traversing unknown
seas the sturdy men who survived all other perils were brought face to
face with starvation when they had ventured too far without turning
back.[371] We need not wonder that the first steps in oceanic discovery
were slow and painful.

[Footnote 371: Or simply because a wrong course happened to be
taken, through ignorance of atmospheric conditions, as in the
second homeward and third outward voyages of Columbus. See
below, pp. 485, 490.]

[Sidenote: The mariner's compass.]

First among the instruments without which systematic ocean navigation
would have been impossible, the magnetic compass had been introduced
into southern Europe and was used by Biscayan and Catalan sailors before
the end of the twelfth century.[372] Parties of Crusaders had learned
the virtues of the suspended needle from the Arabs, who are said to have
got their knowledge indirectly from China in the course of their eastern
voyages.[373] It seems to have been at Amalfi that the needle was first
enclosed in a box and connected with a graduated compass-card.
Apparently it had not come into general use in the middle of the
thirteenth century, for in 1258 the famous Brunetto Latini, afterwards
tutor of Dante, made a visit to Roger Bacon, of which he gives a
description in a letter to his friend the poet Guido Cavalcanti: "The
Parliament being summoned to assemble at Oxford, I did not fail to see
Friar Bacon as soon as I arrived, and (among other things) he showed me
a black ugly stone ca