NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Newton and Halley
From: George Huxtable
Date: 2007 Nov 16, 21:41 -0000
From: George Huxtable
Date: 2007 Nov 16, 21:41 -0000
Nicol�s de Hilster wrote- in response to my quoting Newton's description of the way his instrument was divided- Of course Newton's words sounded challenging to me. If he really meant that he had diagonal scales down to those values what would he have made. When we study his drawing it becomes clear that he left space for the diagonal scale. Assuming his drawing was more or less to scale ... ============================ But the problem is that you can't assume ANYTHING about that engraving. It WASN'T Newton's drawing, which had been lost. It had been drawn by an artist for the Royal Society, and then engraved, long after Newton's death (and after Halley's). It had been drawn from the words of Newton's note. Newton gave the dimensions of the telescope (as three or four feet) but said nothing about the size of the brass plate. It was no more than the imagination of the artist (and then the engraver) that made the plate the same size as the telescope. We are free to interpret the words of Newton's today as we think best, just as the Royal Society artist was free in 1742. And if we think a brass plate of three or four feet across to be impossibly unwieldy (which it would be) then we can make it, say, half the length of the telescope, or whatever we choose. What I am saying is that the engraving that Nicolas is going by is not a document that has any authenticity in itself. It may be, of course, that the original instrument still existed, and was available to be drawn, in 1742. But if it was, I am pretty sure we would have heard about it. None of this detracts, much, from Nicolas' speculation about how it might have been divided. George. contact George Huxtable at george@huxtable.u-net.com or at +44 1865 820222 (from UK, 01865 820222) or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---