Buffon, George Louis le Clerc. Carte Magnetique des Deux Hemispheres. (Amsterdam: J.H. Schneider, 1775. Overall 58 x 95 cm. Binding folds flattened as usual. A double-hemisphere world map designed to display magnetic variation, so centred on the North and South Poles. Buffon has given the position of the supposed magnetic north as being in Canada, to the north of Hudson's Bay and east of Baffin's Bay. Australia is shown with some conjectural elements, good treatment of New Zealand after Cook, detailed treatment of the Nw Coast of America, post-dating the voyages of Cook, but pre-dating Vancouver, with nice detail in the Arctic Circle. Published in the Dutch edition of Buffon's 'Histoire Naturelle', in the mineralogy volumes.