On Thu, 18 Jan 2007 18:12:56 -0500, JohnH wrote:


The scope had one eyepiece. The troops would stop looking through it
because they'd keep the other eye shut while looking. Soon both eyes would
tire. By using the patch over one eye, they could use the scope keeping
both eyes open, which was much less a strain on the eyes. Try just closing
one eye for a couple minutes. You'll feel the strain. Now try just covering
the eye with your hand.

Got it.

--Vic