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17341Re: [multimachine] some interesting reading

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  • Pat Delany
    Jun 22, 2013
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      Great find!
      Too much for me at my age but remember that genius abounds and that many could make use of this information. The genius that Jeremmy showed when he started using Sketchup in one day is all over the place, people just need to know where to find tools.


      From: pokerbacken <no_reply@yahoogroups.com>
      To: multimachine@yahoogroups.com
      Sent: Saturday, June 22, 2013 3:40 PM
      Subject: [multimachine] some interesting reading

      the book "A Treatise on Mathematical Instruments" show how to "construct" measuring instruments (theodolites, rulers, protractors...) with very "primitive" tools and a LOT of time.
      as long as a decent "standard" is used to check the actual measurements the processes in here are quite sound, table of sines and chords are good to have for this.
      Aangular measurements can be "self checking" down to better than arcminute if time is no issue (mirrors first checked with water test used with cross-hairs from spider webb...).
      linear and weight measurements not so easy...

      A Treatise on Mathematical Instruments
      John Fry Heather

      the PDF is here.

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