Trust in Glass: Negotiating the Purchase of the Object Glass for the Airy Transit Circle

Abstract

The Airy Transit Circle of the Royal Observatory, Greenwich is one of the most important instruments in the history of astronomy, navigation and time distribution. However, there has been very little research done on the history of the instrument. This article examines how the purchase of the object glass for the Airy Transit Circle involved active negotiations between George Biddell Airy and three different opticians: Georg Merz, Noel Paymal Lerebours, and William Simms. The article also shows the involvement of John Herschel and Richard Sheepshanks in Airy’s decision making process. By highlighting the presence of these individuals, the article shows how Airy’s trust and distrust in different instrument makers influenced his choice of supplier for the object glass of the Airy Transit Circle.