Thalen-Tiberg magnetometer, with Dahlblom sine arm
Thalen-Tiberg magnetometer, 1880 type, with Dahlblom sine arm, 1928, by Berg
Thalen-Tiberg magnetometer, 1880 type, with Dahlblom sine arm, 1928, by Berg
Thalen-Tiberg magnetometer, 1880 type, with Dahlblom sine arm, 1928, by Berg
Part - tripod
Part - tripod top
Part - box containing two smaller boxes