City Readers Digital Historic Collections at the New York Society Library

The elements of navigation; containing the theory and practice. With the necessary tables. To which is added, A treatise of marine fortification. Composed for the Use of The Royal Mathematical School at Christ’s Hospital, The Royal Academy at Portsmouth, And the Gentlemen of the Navy. In Two Volumes. By J. Robertson, Librarian to the Royal Society, Late Master of the Royal Mathematical School Christ’s Hospital, London; and afterwards, for more than Eleven Years, Head-Master of the Royal Academy, at Portsmouth.

The elements of navigation; containing the theory and practice. With the necessary tables. To which is added, A treatise of marine fortification. Composed for the Use of The Royal Mathematical School at Christ’s Hospital, The Royal Academy at Portsmouth, And the Gentlemen of the Navy. In Two Volumes. By J. Robertson, Librarian to the Royal Society, Late Master of the Royal Mathematical School Christ’s Hospital, London; and afterwards, for more than Eleven Years, Head-Master of the Royal Academy, at Portsmouth.