Dip Needle Magnetism
A transparent full circle graduated plastic protractor is mounted in the frame on the back of the needle. The metal frame can also rotate on its axis to vary the angle of the needle, which can be read by a second mounted protractor. This apparatus is used to measure the dip angle of the Earth’s magnetic field. Consists of a freely moving, vertically suspended magnetic needle 3.75 inch (95mm) long, in a non-magnetic metal frame 4.75 inch (120mm) long. The metal frame is also equipped with two terminals to pass current for advanced experiments in inclination. Base 7.75 inch (200mm) x 4.75 inch (120mm) x 0.5 inch (12mm). Total height, not including the upper edge of protractor 6.25 inch (160mm). A preview of the included instructions can be found at the bottom of this listing.