I have a small collection of steam and air whistles. Among them I have
two Holman Air Whistles. I have looked for a long time to learn
something about this company without any success. They were likely
located on the West Coast. Both of the whistles I have came from
California. I know the Hicks Engine Co. of San Francisco and later of
Yuba City and Benica supplied a 1/2" Holman Whistle with each engine
that had an air compressor. That would have been every engine over 8
HP or all their multi-cylinder engines. These were marine engines
widely used by commercial fisherman in the area in the early 1900's.
The 1/2" size almost certainly refers to the inlet pipe size. Both of
my whistles are larger and I would like to see a picture of a small one.

If anyone has information on the company, a catalog or brochure, where
they were located etc. I would be interested.

Thanks, Ron