I picked up a small 2"X5" notebook that's titled THEORY OF TRAJECTORY SHOOTING SND CONSTANT DELAY..
It also has on page 1 this information.
PATHFINDER TRAJECTORY SHOOTING CHARTS, COPYRIGHT 1935,
HARRY E. GEIST...... SPORTSMAN SCIENTIFIC SERVICE AURORA, IL
The little notebook is like a 2 ring bound notebook.
The contents are trajectory charts.... very detailed, so much in fact, I cannot make heads or tails if it. I'm 78 year young, took physics in high school, but this is gibberish to me.
I'm at a loss at posting photo on this site, but I can send photos to an email address. Please PM me if you can help me figure what this is.
Picked it up at a Minnesota gun show, over 49 years ago
Thank you in advance!