http://www.la84foundation.org/Sports...9/NP1989zv.pdf
The Library of Congress has a number of digitized Spalding Guides including a bunch of "Official Indoor Baseball Guides".
http://memory.loc.gov/ammem/browse/L...ts,+Recreation
click on the Spalding Guides link.
Base lines were between 28 and 35 ft long. The ball was 16 3/4 inches in diameter. The precursor of softball. The bat was 1 3/4th inches in diameter. Seven to nine players on a side.
Played in gymnasiums and National Guard Armories. Competed with basketball.