"So far none has found reason to fault my contention and reasoning posted last week, that the magnetic field does not rotate axially with the physical material of the magnet. " [Robert B] No one but Al Kelly and RB, that is. Here are a few counter-args. Robert I have yet to study what Al Kelly had to say on this. Some comment on yours below. Phil. You are rotating a bar magnet around its long axis - from N to S - and claiming the B field is stationary , because the symmetry of the B field will not cause a difference in measurements of the B field, whether at rest or rotating. Actually No. I am claiming that two counter rotating magnets face to face with an intervening disc rotating with one of them will prove by the measured voltage in the disc, that the field does not rotate with the magnet, that the disc itself moving causes the electrical induction. 1) If the magnetic material were weaker on one side, then the B field would be asymmetric and the rotation of the field would be obvious. True but misleading, and I did acknowledge the effect of "wobbles" which have nothing to do with real rotation, but merely translation. If the the bar magnet was of rectangular cross section, and not symetrical then the position of the field would move with the edges as it rotated. But this does not mean that the field rotated, it just shifts position, same as would happen in any plane of movement. Thanks to enlightenment from Regner, I can call it translation without rotation. In any case we are insisting upon a symetrical field. Are you familiar with how a rotating field is formed in a standard three phase stator? The effect is identical in appearance and effect to a real bar magnet in space being rotated end over end. But no field is moved. It is rather a smooth continuous transition between a decaying field in one space to an increasing field in the next. A resultant between three rotating vectors, but I do not like confusing the practical reality with mathmatical representations of vectors. Or 2) Rotate the magnet around its center , so it moves in the plane of the bar. Again , the B line motion would be clear. As above, again this is merely a shift in position of the field, which must occupy the space related to where it is formed. ie its magnetising force, be it coil or steel. Do you acknowledge that the field decays in its previous position with time, albeit very quickly, just as quickly as the new field is formed in its new space? Using a solenoid coil and variation in current is a clearer way to demonstrate and observe this, but a permanent magnet is just a different kind of solenoid with moving electron charges. So the B lines rotate with the source for all asymmetric fields. But suddenly stop rotating when the lines are symmetric? As I have said elsewhere, lines as such do not exist. They are a graphical representation of conventions, to allow for theoretical applications.(Applied theory) Again the field as an entity does not move. It is an illusion of movement, caused by a continuous succession of decay and expansion. I believe the field can be translated in a rotation, but not itself rotated. 3) In the case of the Earth's B field, a charge at rest at the equator (for maximum effect) would be moving at 1000 mph through static B lines, causing a vertical magnetic force qvB.. But this is not observed... at the equator or anywhere else. Beautiful.. which means according to my rationale that the earth is not spinning, the 1000mph is a fiction, (exempting relative motions of the aether of course) if we can agree or come to agree that the field of the earth does not rotate. This raises that other question for another time: How does the magnetic/electric field relate to the movement of the aether? For v, Maxwell and relativists use the speed of the charge relative to the B lines, which equals zero, so the absolute motion can't be distinguished. Maybe yes, if my claim, that the field is not axially rotating with the steel or coil or planet earth cannot be proved . RB Robert a diagram for you to ponder. The question. Is the field across the gap G rotating at 5000rpm ? Your formula "causing a vertical magnetic force qvB" which I did not think of, could be applied here. What if we suspended an electrostatically charged pith ball in all three gaps centres? If the field was rotating a force should be detected. I guess the air flow would make this impractical at the magnet gaps but there is always a way. . ...Philip. ------------------------------------------------------------------------------ No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.20.6/1280 - Release Date: 15/02/2008 9:00 AM