Today in 1897, US Patent 581206 A was issued, an invention of Peter Cooper Hewitt, for his “Apparatus for Aerating Liquids.” There’s no Abstract, although in the description it includes this summary:
My invention is applicable to aerating waters, beer, and other liquids.
In the manufacture of beer by some methods the carbonic acid in the beer is extracted and it becomes necessary to replace the gas thus taken out.
The object of my invention is to thoroughly aerate the beer while it is in the form of a highly-attenuated film.
My invention consists in a centrifugal machine of peculiar construction adapted to reduce the liquid to the form of an extremely thin film, the centrifugal machine being operated in a closed vessel suitable for the required pressure.