Here's one that I've always wondered about:
The 1935 $20 note was originally issued with a "large" seal, the same as the $1, $2, $5, $10 and $25 notes. The $50, $100, $500 and $1000 notes where all issued with a "small" seal. At some point, the $20 note ended up with the small seal as well.
- Why did they use two sizes of seals? What this a "higher security" (harder to duplicate) device for the larger denominations?
- Why did they change the $20? If the smaller seal was a security thing, did they switch the $20 because back then $20 was considered a "high denomination"?
- And the $25 note, did it stay as a "large" seal because it was such a short issue, the opportunity never arose to reprint with the smaller seal?
{http://www.cdnpapermoney.com/images/35s/1935_20f.jpg}