Two important American whistles long searched for by whistle collectors
were found April 2019.
Alexander P Hatch Patents were thought as none existing, since none were seen and the patents applied for stated no model examples.
As to rarity we know of another Plural whistle I discovered with a long time U.S.A collector in 2016, The Police one is the only example I know of.
I imagine there are more to be discovered and there is a good chance that the more fancy variation with few combined whistles as seen on the same patent of the plural whistle is somewhere out there… (so it is with the British Plural one that I posted the patent for last year, no actual example ever seen  – it is from the same period)
keep your eyes open it is a treasure probably worth well over a 1000, hopefully with more exposure to the ones that just surfaced more will show up in the future.
It is a pity that there is no information about this inventor who was a citizen of Bridgeport Connecticut at the time, I am sure an extensive research can reveal much more as to his life,  Albeit the fact that his whistle patents are among the most cited by whistle inventors, dozens of newly patented whistles since then quote his patents, including 21st century ones.

Alexander P. Hatch American Whistle patents App. for 1899 & 1901
Both are made of Nickel Plated Brass.

I highly recommend reading carefully the patents description & drawings in the next links.
The one on left side is know as the plural whistle and you may see the patent drawings and description HERE at google patent  storage
It was found with the original chain in an old bicycle store, in mint condition.
The whistle on the right a tube whistle with unique design and partition is stamped
POLICE DEPARTMENT and has patent date as well see google patents HERE
All rights reseved to A. Strauss Whistle museum
we are glad to help with any questions regarding whistles,
please attach photos to questions, Email: info@avnerstrauss.com