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Fred Hebard wrote-

| Newton apparently independently invented the double-reflecting
| instrument 20-30 years ahead of Godfrey & Hadley(?, not sure if the
| English guy was Hadley), and gave a secret presentation to the Royal
| about it.

=============

Yes, the "English guy" was Hadley.

Newton did indeed show his double-reflecting instrument to the Royal 
Society, in 1699. It was referred to in the Society's minute-book, but was 
never fully published as a paper until long after Newton's death, and after 
Halley's death, when the details were found among Halley's papers. So it 
wasn't publicised at the time, though it was hardly "a secret presentation". 
Halley acknowledged taking Newton's instrument to sea, in his Atlantic 
voyages for surveying the variation.

Newton's instrument was identical, except in detail, to Hadley's and 
Godfrey's. He was a long way ahead of his time.

=================

By the way, though it's often quoted that the Longitude Prize offered 
�20,000 if the longitude could be found to 1 arc-minute (which it did), it 
also offered a lesser prize of �10,000 if anyone could measure it to within 
2 arc-minutes. So a lot of cash was hanging on the small-details of the 
performance of a longitude method.

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. 


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