in ordinary weather dead-reckoning is very accurately calculated by the
number of revolutions of the propellers recorded in the engine-room; and
a device not unlike this was known to the Romans in the time of the
Republic. They attached small wheels about four feet in diameter to the
sides of their ships; the passage of the water turned the wheels, and a
very simple gearing was arranged which threw a pebble into a tallypot at
each revolution. This device, however, seems to have been abandoned or
forgotten in Columbus's day, when there was no more exact method of
estimating dead-reckoning than the primitive one of spitting over the
side in calm weather, or at other times throwing some object into the
water and estimating the rate of progress by its speed in passing the
ship's side. The hour-glass, which was used to get the multiple for
long distances, was of course the only portable time measurer available
for Columbus. These, with a rough knowledge of astronomy, and the
taking of the altitude of the polar star, were the only known means for
ascertaining the position of his ship at sea.


The first mishap occurred on Monday, August 6th, when the Pinta carried
away her rudder. The Pinta, it will be remembered, was commanded by
Martin Alonso Pinzon, and was owned by Gomaz Rascon and Christoval
Quintero, who had been at the bottom of some of the troubles ashore; and
it was thought highly probable that these two rascals had something to do
with the mishap, which they had engineered in the hope that their vessel
would be left behind at the Canaries. Martin Alonso, however, proved a
man of resource, and rigged up a sort of steering gear with ropes. There
was a choppy sea, and Columbus could not bring his own vessel near enough
to render any assistance, though he doubtless bawled his directions to
Pinzon, and looked with a troubled eye on the commotion going on on board
the Pinta. On the next day the jury-rigged rudder carried away again,