Lodestones were used as an early form of magnetic compass. It is also the term for the graduated markings found on the traditional magnetic compass. The development of the magnetic compass is highly uncertain. Inventions such as gunpowder, woodblock printing and the magnetic compass were improved upon. In 1399, an Egyptian reports two different kinds of magnetic compass. Unlike a magnetic compass, it does not seek north. The invention of the magnetic compass, telescope and sextant enabled increasing accuracy. The thirteenth century saw the rise of the magnetic compass for overseas travel. The history of feng shui covers 3,500+ years before the invention of the magnetic compass. A magnetic compass provided a sense of direction. In his "buxolarum" [=magnetic compass] workshop he was helped by his son Jafuda. Pilots must compensate for such errors when using the magnetic compass. The magnetic compass is the most familiar compass type. The sea turtles also contain an internal magnetic compass. The primary instrument of navigation is the magnetic compass.