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Practical navigation, or, An introduction to the whole art : containing the doctrine of plain and spherical triangles : plain, mercator, great-circle sailing, and astronomical problems : the use of divers instruments ... : sundry useful tables in navigation, and a table of 10,000 logarithms, and of the logarithm-sines, tangents, and secants / by John Seller. Public Domain Mark. Source: Wellcome Collection.