saying that he had, ready for publication, a Draught of the River St.
Lawrence with its harbours, bays, and islands, and asked for their
Lordships' directions thereon. With their Lordships' approval it was
published, and may be found at the end of The North American Pilot,
London, 1775, together with other maps, some of which are Cook's work. At
the commencement of the book is a letter from Cook to the compiler of the
volume, congratulating him on the collection, and referring to the fact
that some of the charts contain his work, but he does not lay claim to
any special ones. On Saunders' chart there is a long note which
concludes:

"The distances between Isle Coudre and Isle of Orleans, the Pillar Rocks
and Shoals in the south channel were accurately determined by triangles.
The other parts of this chart were taken from the best French Draughts of
this River."

It is doubtful if this triangulation could have been carried out by Cook
during his passage up and then down the river, the only time he had in
1759, but if it were, it argues much greater knowledge of nautical
surveying than he is generally supposed to have had at the time.

During the winters that the Northumberland stayed in Halifax Harbour,
Cook employed his spare time in improving his knowledge of all subjects
that were likely to be of service to him in his profession. He read
Euclid for the first time, and entered upon a study of higher
mathematics, especially devoting himself to astronomy. King in his sketch
of Cook's life, says, on the authority of the man himself, that these
studies were carried on "without any other assistance than what a few
books and his own industry afforded him."