on a flat-roof structure. The dome is a 20-sided conical shell 100 feet in diameter and 50 feet in height. As it is prefabricated, larger or smaller domes can be erected simply by adding or deleting rings. The first test structure was built in 1968 at a cost of C$17,000. The result was so successful that between 1968 and 1978, approximately 200 structures were erected in Ontario. John Fitzpatrick was granted a patent in 1972 for the invention. These structures continue to be used in Canada and internationally. While serving at the Ministry of Transportation in Ontario in the 1970s, John Fitzpatrick devised a bubbling system used in the St. Lawrence River to prevent ice from forming in the winter. The formation of ice had hindered ferries from connecting the people of the Frontenac Islands to the mainland. The invention pumps compressed air through a network of perforated pipes at the river bottom that run between the docks and along the routes of the ferries. The bubbles hinder ice from forming which allows the ferries to function regularly in the winter. Death Fitzpatrick died on July 9, 1989 in Toronto at the age of 82. His resting place is at the Sanctuary Park Cemetery in Toronto. References Further reading Hawley, Samuel (2002). I Just Ran: Percy Williams, The World's Fastest Human. Vancouver: Ronsdale Press 1907 births 1989 deaths Canadian male sprinters Olympic track and field athletes of Canada Athletes (track and field) at the 1928 Summer Olympics Athletes (track and field) at the 1930 British Empire Games Commonwealth Games gold medallists for Canada Commonwealth Games silver medallists for Canada Commonwealth Games bronze medallists for Canada Commonwealth Games medallists in athletics Players of Canadian football from Ontario Hamilton Tigers football players Athletes from Toronto 20th-century Canadian inventors 20th-century Canadian engineers Royal Canadian Mounted Police officers Medallists at the 1930 British Empire Games