Liquid Fuels Explained

If you ever wondered where liquid fuels come from, here is a short primer.

Row crop tractor
Huber Modern Farmer row crop tractor, S/N 10819, year1931. l have owned this tractor 23 years. I would like to know ifthere are other Hubers of the row crop still in use. Courtesy of Gilbert Tweedt, Corsica, South Dakota