The sun, like the earth is now known to be a magnet, whose general magnetic field is about 80 times as intense as that of the earth. At the distance of the earth the solar magnetic field is not appreciable, “since the effect of one pole counteracts the equal and opposite effect of the other pole.” Were it not for our knowledge concerning the Zeeman effect, it would not yet be known for a certainty that the sun is a vast magnetic globe, since this fact could not be assumed to be a source of the sun’s gravitational power. “Indeed,” says Dr. Hale,[29] “its attraction cannot be felt by the most delicate instruments at the distance of the earth, and would still be unknown were it not for the influence of magnetism on light. Auroras, magnetic storms, and such electric currents as those that recently deranged several Atlantic cables are due, not to the magnetism of the sun or its spots, but probably to streams of electrons, shot out from highly disturbed areas of the solar surface surrounding great sun-spots, traversing 93 million miles of the ether of space, and penetrating deep into the earth’s atmosphere.” By means of the famous 150-foot tower telescope at Mount Wilson, which produces at a fixed point in a laboratory an image of the sun about sixteen inches in diameter, the magnetic phenomena of sun-spots are being studied to great advantage, the enlarged sun-spots making possible separate observation of their various parts. “This analysis is accomplished with a spectroscope 80 feet in length, mounted in a subterranean chamber beneath the tower.” By this means the very important discovery was made by Director Hale that the entire sun, rotating on its axis, is a great magnet. “Hence,” says Dr. Hale, “we may reasonably infer that every star, and probably every planet, is also a magnet, as the earth has been known to be since the days of Gilbert’s ‘_De Magnete_.’ Barnett has succeeded in producing magnetism by rapidly whirling masses of metal in the laboratory” (Hale, “The New Heavens,” Pages 69-70). More recently (October, 1922), Hale, Ellerman and Nicholson, all of the Mount Wilson Observatory, have detected _invisible_ sun-spots by searching for evidences of the Zeeman effect in promising regions, such as areas of flocculi following a large spot. “A special polarizing apparatus permits very small magnetic fields to be found by the alternate widening to red and violet of the iron triplet Lambda 6173,” say Hale and Adams (“Summary of the Year’s Work at Mount Wilson,” Publications of the Astronomical Society of the Pacific, October, 1922, Pages 269-70 [Vol. XXXIV, No. 201]). “The results confirm the view that a spot represents a vortex, which becomes visible only when the cooling due to the expansion (of gases) is sufficiently great to produce a perceptible decrease in the brightness of the photosphere.”