With this view of the case we are now in a position to answer a question asked by Professor Schuster at the British Association in 1892. He asked, "Is not every large rotating mass a magnet?" and added, "If it is, the sun must be a powerful magnet. The comets' tails, which eclipse observations show stretching out from the sun in all directions, probably consist of electric discharges." Now, in relation to this question, the answer is that every rotating body in the Aether is undoubtedly an electro-magnet. Thus, not only is the sun an electro-magnet, but every planet and satellite, and every meteor that rotates in the electro-magnetic Aether, is converted into a magnet, partly by that rotation, and partly by the currents induced in the Aether by that rotation. We shall also find when we come to deal with the phenomena of comets' tails, that Professor Schuster is also right as to their cause, and that they are due to electro-magnetic repulsions originated in the Aether by the sun, which is an electro-magnet. [Footnote 39: _Outlines of Astronomy_, Herschel.] ART. 92. _Cause of Rotation of the Earth on its Axis._--If there is one fact true in relation to the earth as a planet, it is that the earth rotates on its axis every 24 hours. Day in and day out, for centuries past, this revolution has taken place as the earth journeys in its annual path round the sun. Not only does the earth rotate on its axis, but every other planet rotates on its axis in varying times, as the following table shows-- HRS. MIN. SEC. Mercury 24 5 0 Venus 23 24 0 The Earth 23 56 4 Mars 24 37 23 Jupiter 9 55 0 Sarturn 10 14 23 Uranus ? Neptune ? Further, the sun also rotates on its axis in a period of 26 days. Here, then, are certain phenomena in connection with the solar system, for which up to the present no explanation as to the physical cause of rotation has ever been offered. Surely there is some physical cause, to account for such a rotation, and if there be a physical cause, then the problem to be solved is--find the physical cause to account for the continuous and ever-recurring rotation of all the planets and the sun on their axes, which shall be so effective and continual that, year in and year out, the rotation of all the planets may be continued as observed. In solving this problem we have to revert to our reason why the earth is a magnet. In Art. 91 we learned that the earth and all the other planets, and indeed all stellar bodies, were electro-magnets, because the electro-magnetic Aether was constantly circulating round them.