OF course my readers know all about geometry, but if by the rarest of
chances one of them should not it will not prevent him from using that
science to square the corners of his log cabin. Builders always have a
ten-foot measuring rod--that is, a rod or straight stick ten feet long and
marked with a line at each foot from end to end. Make your own ten-foot
pole of as straight a piece of wood as you can find. With it measure six
feet carefully on the log _C_, _G_ (Fig. 180) and mark the point at _O_
(Fig. 180); measure eight feet on the other log _C_, _A_ (Fig. 180) and
mark the point at _N_. If these measurements have been carefully made from
_C_ to _O_ and from _C_ to _N_ and your corner is "square," then your
ten-foot pole will reach between the two points _O_ and _N_ with the tips
of the pole exactly touching _O_ and _N_. If it does not exactly fit
between _N_ and _O_, either the corner is not square or you have not
marked off the distances accurately on the logs. Test the measurements and
if they are not found true then push your logs one way or the other until
it is exactly ten feet from _O_ to _N_. Then test the corner at _H_ in the
same manner.
Fig. 180. Fig. 181. Fig. 182. Fig. 183.
[Illustration: How to square the corners, roll the logs of cabin, and make
log steps.]