How did scientists get to know that magnetic field lines travel from South to North Pole inside the magnet - Science - Magnetic Effects of Electric Current

Question

How did scientists get to know that magnetic field lines
travel from South to North Pole inside the magnet?

Vipra Mishra · Accepted Answer

Dear Student

When magnetic field lines are traced with help of magnetic compass
it is found that magnetic field lines start from North pole and
goes towards South pole

<img alt="" src=
"https://s3mn%20mnimgs%20com/img/shared/content_ck_images/ck_5a7e90e073e7c%20png"
style="width: 290px; height: 174px;">
As magnetic field lines form closed loop therefore inside magnet
they travels from South to North

Regards

How did scientists get to know that magnetic field lines travel from South to North Pole inside the magnet?