Important note: A Report of the Commissioner
of Internal Revenue to the Bureau of Engraving and
Printing, stated that the USIR watermarks were to be
placed in such a manner that each stamp would have at
least part of one or more letters visible and that each
square inch of the paper the stamps were to be printed on
would contain one letter. We are of the opinion that this
is the case for the single-line watermarks as well. Thus
the horizontal spacing from the middle of one letter to
the next should be approximately one inch, and the vertical
spacing from the bottom of one letter to the bottom of the
next should also be approximately one inch. Examination of a
large block of single-line watermarked stamps seems to bear this
out and we have no reason to reject this theory. If the
reader has any reference that either supports or refutes
this contention, we invite their input.