The use of densitometers is widespread over many different industries. These range from food & beverage industries to petro-chemical and pipeline transmission. This paper will cover the installation and operation of densitometers in the petroleum pipeline industry. It will also discuss pycnometers used to calibrate densitometers. In using a pycnometer, you must have the correct scales, pressure gauges and thermometers. You will learn the steps necessary to install, operate and calibrate the instrument.