Sealy's collections of moths, butterflies, and birds' eggs are held by the South Canterbury Museum in Timaru. Sealy owned a first edition of Walter Buller's book A History of the Birds of New Zealand and amended it with his own notes and drawings of bird eggs. The South Canterbury Museum purchased Sealy's book in 2008 to add it to their collection. Many of his photographs are held by the South Canterbury Museum and Canterbury Museum in Christchurch. Von Haast named a number of geographic features in the Southern Alps for him, including Mount Sealy and the Sealy Tarns in the Sealy Range. Sealy Glacier, which feeds Sealy Stream, located in South Westland, are probably also named for Sealy. Sealy Pass above the Godley Glacier commemorates Sealy's 1869 exploration of the glaciers.