Brownian Movement Apparatus for Detecting Molecular Motion w/ Directions for Use

Description

This 7" long instrument from Frey Scientific Co. provides an indirect means  to observe motion in molecules of air. Smoke is introduced into the tube and when currents stop swirling  the large smoke particles when seen under a microscope will be shouldered aside by the smaller air molecules bouncing off of them.  The item is at least 20+ yrs. old.  Shipping is free via 1st class mail.