4 ms·

Happy to see this post on HN. As a college prof, I've spend many years studying the history of 1700s navigation and taking student groups to Greenwich to see a

Happy to see this post on HN. As a college prof, I've spend many years studying the history of 1700s navigation and taking student groups to Greenwich to see and study H1 (H2, H3 and H4). I love these clocks and all of the stories behind them. The serious enthusiast will find a lot of technical details on the Harrison's clocks in this book https://www.amazon.com/Marine-Chronometers-Greenwich-Catalogue-National-ebook/dp/B079TBK8NB/ https://www.amazon.com/Marine-Chronometers-Greenwich-Catalog... and this one https://www.amazon.com/Marine-Chronometer-Its-History-Development/dp/B0CJLKZ41X/ https://www.amazon.com/Marine-Chronometer-Its-History-Develo.... I've also collected all of my pedagogy on 1700s navigation into a this book: https://www.amazon.com/Longitude-Time-Navigation-Tom-Bensky-ebook/dp/B00HKMCE0A/ https://www.amazon.com/Longitude-Time-Navigation-Tom-Bensky-... where I dive somewhat into the innards of H1. To answer another post: H1 has been fully disassembled and reassembled with XRF done throughout.

hilbert42 3y ago
"...fully disassembled and reassembled with XRF done throughout. Well, hopefully, that answers my point about the clocks' materials and an XRF analysis. Did that reveal anything of significance? From points/questions raised by James Stanley and my ignorance of this recent work it seems these facts ought to be more widely known. (Ouch, the price of Marine Chronometers at Greenwich unfortunately has to mean that information is confined to Diehards.)
jstanley 3y ago
Is there a way to buy your "Longitude, Time and Navigation" book as a physical book?
- tbensky 3y ago
  Hello and thanks for our interested. There's a paperback version here: https://www.amazon.com/Longitude-Time-Navigation-Tom-Bensky/dp/1729358241 https://www.amazon.com/Longitude-Time-Navigation-Tom-Bensky/... (same ed. as the Kindle version).
  - jstanley 3y ago
    Neat, thanks! I've ordered a copy.
kwhitefoot 3y ago
XRF?
- tbensky 3y ago
  XRF=x-ray fluorescence. You shoot X-rays into a metal, typically the gamma rays from an Am-241 source. This causes atoms in the metal to fluoresce their own gamma rays that are a (somewhat) unique signature of the atom itself. So in sum, XRF allow one to non-destructively determine the atomic constituents of a bulk material (but 'heavy' materials..heavier than Silicon for example).

hilbert42 3y ago

"...fully disassembled and reassembled with XRF done throughout. Well, hopefully, that answers my point about the clocks' materials and an XRF analysis. Did that reveal anything of significance? From points/questions raised by James Stanley and my ignorance of this recent work it seems these facts ought to be more widely known. (Ouch, the price of Marine Chronometers at Greenwich unfortunately has to mean that information is confined to Diehards.)

jstanley 3y ago

Is there a way to buy your "Longitude, Time and Navigation" book as a physical book?

tbensky 3y ago
Hello and thanks for our interested. There's a paperback version here: https://www.amazon.com/Longitude-Time-Navigation-Tom-Bensky/dp/1729358241 https://www.amazon.com/Longitude-Time-Navigation-Tom-Bensky/... (same ed. as the Kindle version).
- jstanley 3y ago
  Neat, thanks! I've ordered a copy.

kwhitefoot 3y ago

XRF?

tbensky 3y ago
XRF=x-ray fluorescence. You shoot X-rays into a metal, typically the gamma rays from an Am-241 source. This causes atoms in the metal to fluoresce their own gamma rays that are a (somewhat) unique signature of the atom itself. So in sum, XRF allow one to non-destructively determine the atomic constituents of a bulk material (but 'heavy' materials..heavier than Silicon for example).