Re: anachronisms?

: John Schilling <schillin@[EMAIL PROTECTED]
>
: As those techniques evolved quite rapidly over the sixteenth
: century, there was only a narrow window for dead reckoning to
: serve as a primary navigational technique.  A narrow window
: during which a whole lot of quite skilled navigators and their
: crews, sailed out on the open sea and never made their way home.

Seems like.  I don't know if anybody's mentioned:

:: What the later medieval and early modern sailors did was every hour
:: they measured the speed and direction (with a compass) of the ****p. 

that you can only measure "speed and direction" wrt the ocean surface.
The difficulty (*amongst* our many difficulties) is that there are ocean
currents, which can displace you an unknown distance and direction of
tens or hundreds of kilometers per day.

Now sure, if you've charted all the mid-ocean currents you can maybe
correct for some of that.  But there's a boostrapping problem.

And a fanatical devotion to the pope.


Wayne Throop   throopw@[EMAIL PROTECTED]
   http://sheol.org/throopw