NavList:

Alex wrote in Navlist 858

| Dear Frank,
| This statement is very interesting (and misterious):
|
| > I'll have to  dig up the reference on this,
| > but it's interesting to note that
| > the earliest  references to backlash come from the 18th century
| > --long before
| > the micrometer.
|
| Please post the reference when you dig it out.
|
| When I think of the construction of the usual vernier sextant
| I cannot imagine any backlash in its operation,
| and I don't see how friction of the arm
| against the arc can be relevant.
| Maybe they (and you) mean that the arm of the sextant
| gets slightly bent in a direction parallal to the arc,
| because of the friction in the pivot?

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

I had also addressed the same matter, in Navlist 798, but Alex does
not mention that message. Did he receive, and read it?

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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