Fig. 3From: In search of America’s old covered bridgesTheodore Burr’s original patents were lost in a Patent Office fire in 1836. This recreated drawing is his U.S. Patent No. 2769X, April 3, 1817 (Source: https://pdfpiw.uspto.gov/.piw?Docid=X0002769&idkey=NONE&homeurl=http%3A%252F%252Fpatft.uspto.gov%252Fnetahtml%252FPTO%252Fpatimg.htm)Back to article page