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; as also of the plain chart, mercator's chart, and both globes. Sundry useful tables in navigation: and a table of 10000 logarithms, and of the logarithm sines, tangents, and secants. All carefully corrected. By John Seller, hydrographer to the king.