US 1615 7.9 Cent, Why?

Ok, I'm a noob, but what is the point of issuing a stamp of 7.9 cents? The same question with 1614 with value 7.7 cents? Why the fraction of a cent?

These were special stamps issued for rates other then first class, like bulk mail, presorted mail, nonprofit mail etc. These rates still exist although individual stamps are no longer issued.


Peter

These are fairly self-explanatory, part of a continuing series of fractional values for 3rd-class "bulk rate" mailings.



Fractional values for various mailing categories are very prominent in the later transportation coils series. The coil format makes it easy to apply them with automatic machinery. Many of these and later mailings are "false frankings" where the mailer applied a stamp like Scott 2602-2604 (to simulate first class mail and have a better chance of being opened) and paid the difference up to the exact rate on the side.

Great thanks for clearing that up : )