Re: anachronisms?

On Jan 16, 12:13 pm, thro...@[EMAIL PROTECTED]
 (Wayne Throop) wrote:
> : John Schilling <schil...@[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.

If you read the article I quoted you can see that Columbus took that
into account  in an area he knew nothing about.



>
> And a fanatical devotion to the pope.
>

???

Please explain
> Wayne Throop   thro...@[EMAIL PROTECTED]
  http://sheol.org/throopw