Student's handbook of paints, colours, oils and varnishes (1903)
Furnell, John · London : Scott, Greenwood & Co. ; New York : D. Van Nostrand · leaf 79
SECTION XV. Spirit Varnishes, Polishes, Stains, Etc. THESE are generally manufactured in the cold state by using large barrels or churns, with runners or shelves let in the staves, which cause the gums put in them to dissolve more readily in the spirit as they revolve. The barrels are made to hold… … and spirit, and the makes or recipes are calculated accordingly. By looking at the sketch a good idea may he obtained of the spirit varnish churns, of which large numbers are employed in paint factories. The bung hole is fitted with a screwed flange and a cap with a round piece of leather inside,…
Paint · Color · Varnish and varnishing
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.