During this time he helped develop the lighthouse optics for Chance's fledgling operation, as well as other optical glass, such as a flint and crown glass disc, measuring 29-inches (74cm).
He helped develop the lighthouse optics for Chance's fledgling operation, as well as other optical glass-inches (74cm). This was such as a flint and crown glass disc. This was during this time. Other optical glass was measuring 29.