by William Gilbert, On the Magnet — Book IV. Chap. 20… (1900)
“ For in no region or place in the whole world, of not greater latitude, is there so great a deviation; and, in reality, there the deviation is slight. Also when they make out that at Mosambique the compass deviates by one rumbe to the north-west, it is false; even though they use (as they are accustomed to do) the Portuguese compass: for beyond all doubt on the shore of Mosambique the versorium inclines 1⁄4 rumbe or even more to the south-west. ”
