5308238 Joseph Priestley\'s gun barrel apparatus.; (add.info.: Engraving depicting Joseph Priestley\'s gun barrel apparatus which he used when he wished to examine gases from various substances subjected to heat. Priestley placed the substance under investigation in the closed end of barrel which he filled with burned sand. Pipe or glass tube was luted to pen end of the barrel. End of the barrel is placed in the fire and tube placed in a bath of mercury suspended from the mantle shelf, and gas is collected. Joseph Priestley (1733-1804) an English Separatist theologian, natural philosopher, chemist, innovative grammarian, multi-subject educator, and liberal political theorist. Dated 18th century.); Universal History Archive/UIG.