Question

Information about how the merchant of olden times used a magnet while travelling

Answer 1

They used it in compass for know the directions while traveling

Answer 2

The first documented use of a compass dates back to 70 century A.D in China but then it was used for construction purposes. In the year 1187 A.D. a European Alexander Neckam used the magnetic compass to navigate through the English Channel.

The magnet in the compass is aligned with the magnetic North Pole. So finding the east, west and south is easy when you know the direction of the north.