"The method of reading angles of different degrees and in that way
getting heights and distances. That's the way they measure mountains
that can't be climbed and tell the distance of stars."

"Shucks, young feller! I don't reckon anybody kin tell the distance o'
the stars; they only put up a bluff on that. They ain't no ackshall way
o' gittin' distance onless you lay a tape measure, er somethin' like it
on the ground. These here surveyors all does it; I had 'em go round my
place."

Bill smiled and shook his head. "I guess you just haven't given it any
consideration. There are lots of easier and better ways. Triangulation.
Now, for instance, suppose an army comes to a wide river and wants to
get across. They can't send anybody over to stretch a line; there may be
enemy sharp-shooters that would get them and it is too wide, anyway. But
they must know how many pontoon boats and how much flooring plank they
must have to bridge it and so they sight a tree or a rock on the other
shore and take the distance across by triangulation. Or suppose--"

"Never heard of it. Why wouldn't surveyors git from here to yan that
a-way, 'stead o' usin' chains? Could you----?"

"Chaining it is a little more accurate, where they have a lot of curves
and angles and the view is cut off by woods and hills. Yes, we can work
triangulation; we could tell the distance from the hilltop to your house
if we could see it and we had the time."

"Bunk! Don't let 'em bluff you that a-way, Uncle. Make 'em prove it."
Thad showed his open hostility thus.