First Flight Covers and more

another cover in that same lot that caught my eye was this one ... I've been fascinated by the "Black Hardings" for a long time. I always keep my eyes open for covers and/or collections that contain these stamps. This cover immediately drew my attention. Lots going on here, but the main attraction was that pair of Black Hardings down in the corner. I'm quite sure without measuring that they are NOT the elusive Scott #613 ... but it's still a nice cover!

Hi Clif,
The cognoscenti are obviously being polite and waiting a bit to allow me to attempt a reply about that Franklin stamp with the guide line on top.  I'm guessing they were printed in sheets of 400, then apparently cut into panes of 100 along the central vertical and horizontal guide lines before perforating and distributing to post offices.   So the stamp would have been in the 11th row of the 400 stamp sheet, but in the top row of its pane.  

EDIT:  The green Franklin coil stamp in the previous post also has a guide line.  That one I'm clueless about.

So in each sheet of 100 there would be 4 stamps with TWO straight sides? Or were the edges perforated?

You are correct, 4 stamps with two straight sides that were not perforated.

Here is a pane of 100 stamps after being cut from a sheet of 400....

A bit of speculation regarding the first cover in this thread--the one addressed to Austria--which was carried on CAM 11's first eastbound flight...

My guess is that the sender might have mailed the cover inside of a larger envelope to the postmaster in Cleveland, asking that it be postmarked and placed on the first Cleveland-Pittsburgh flight.

Another possibility is that the sender lived in Los Angeles but happened to be in Cleveland at the time the flight was taking place, but that seems rather less likely.

In either case, yes, you're on the right track--Cleveland to Pittsburgh was just one part of the journey.