The seat is made from the dense hardwood called Lignum vitae. The pit wheel is cast iron with 96 lignum vitae cogs. Hardwoods include big-leaf, little-leaf, and African mahoganies, ebony and lignum vitae. American folksinger Pete Seeger fashioned the neck of his trademark banjo from lignum vitae. The problem was solved with a lignum vitae water-lubricated bearing, patented in 1858. They are close relatives of the "true" "lignum vitae" trees of genus "Guaiacum". Pioneering calypsonian/vaudevillian Sam Manning recorded a song entitled "Lignum Vitae" in the 1920s. The historical material used for this was the tropical hardwood timber, lignum vitae. Bowling balls were made of lignum vitae (hardwood) until the 1905 introduction of rubber balls. In this case the Lignum vitae is from the "Guaiacum officinale" tree. The national flower of Jamaica is the lignum vitae ("Guaiacum officinale"). Early versions are made of "lignum vitae" (Latin for "wood of life"), the densest hardwood. On July 30, 2016, "Lignum Vitae" intercepted a small boat with eight Cuban refugees aboard.