[AT] OT pocket knives

[charlie hill]

I'll see if I can find it.  I was trying to remember from almost 50
years ago something we were taught in Engineering Graphics.
I can't remember the details but there was a curve (sine curve or whatever)
drawn above the line on a drawing sheet and somehow using drafting 
instruments
we transferred measurements from the curve to the area below the line
forming another shape (maybe a straight line?) that represented the 1st 
derivative of
the curve.   Does that sound at all right?   I just can't remember the 
details.  I remember
at the time being somewhat amazed at the process because of it's simplicity 
and result.

Charlie


-----Original Message----- 
From: rlgoss at twc.com
Sent: Tuesday, July 14, 2015 6:33 PM
To: Antique tractor email discussion group
Subject: Re: [AT] OT pocket knives

BINGO! I found an article on-line about this planimeter, folks.  It even has 
a
name -- Prytz or Hatchet planimeter.  for a good discussion (complete with
illustrations, formulas, etc.) search for make-shift planimeter, and go to 
the
PDF written by professors from Wabash and Western Connecticut --Area Without
Integration: Make Your Own Planimeter.  After reading this article, I 
remember
having made one of these out of a straightened clothes hanger.


Larry
_______________________________________________
AT mailing list
http://www.antique-tractor.com/mailman/listinfo/at