Mud Still 2` : An instrument used to distill oil, water, and other volatile material in a drilling fluid to determine oil, water, and total solids contents in volume-percent. (Bul D11)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}