This section is from the book "Spons' Mechanics' Own Book: A Manual For Handicraftsmen And Amateurs", by Edward Spon. Also available from Amazon: Spons' Mechanics' Own Book.
Turpentine varnish consists of 4 lb. common (or bleached) rosin dissolved in 1 gal. oil of turpentine, under slight warmth. It is used for indoor painted work, and also to add to other varnishes to give them greater body, hardness, and brilliancy.