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George Huxtable wrote:
> There is some serious misunderstanding going on.
>
> Mike Daly questioned Ted Gerrard's account

First misunderstanding - I only commented on Nicolas' speculation on why
  Newton's instrument wasn't manufactured or used in significant
numbers.  I have not made any relevant comment on Ted's posts.

> So what did the artist of that drawing
> have to go on? As far as we know, only Newton's text, and no "attached
> scheme". No doubt, he interpreted that text as best he could, with the help
> of the experts of the day, but that doesn't make that drawing an authentic
> representation of what Newton's scheme would have been. And then, in another
> indirect process, that so-familiar engraving was made, presumably from that
> drawing. There are discrepancies to be found between those three documents,
> the letter, the drawing, and the engraving, which Ted Gerrard goes into,
> though I don't go along with Ted about the importance of every such detail.

Second misunderstanding.  The drawing is irrelevant.  I know what the
text says and it states the instrument is a brass plate with a
three-four foot scope attached.  What is the problem here?

> | So - why would someone willingly look forward to holding and taking
> | measurements using a triangle of brass with a 3-4 foot telescope on it?
>
> I'm not sure what point Mike is trying to make here. You have to make the
> best of what the technology of the day allows.

Compared to a long telescope for a lunar method with no reliable tables
for general use? - I'd say the technological choice is a Davis Quadrant
and a ship's log.  For something as simple as meridian altitude, the
Davis quadrant wins hands down in the eyes of a mariner in 1700.  This
discussion is about a crude instrument that appears roughly 70 years
before lunars are ready for prime time.

Mike




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