If Precession is caused by the Magnetic Field, then the Coriolis Effect must also be caused by the Magnetic Field, Precession, an Effect, and the Coriolis Effect, also an effect both effects seen after the fundamental
The model I was considering at the time was a spinning gyroscope inclined at 90° to the earths surface with one end of it's axle supported by a post, and the other end not supported. The gyroscope had not charge nor associated field/s. I am aware that there is a mass field associated with spinning masses but that is way above my head, and have been assured that it is not of enough magnitude in my little gyroscope to bother with so I was more than happy to ignore it. The earths magnetic field is not of sufficient magnitude to have any appreciable affect on a little brass gyroscope.
I initially wanted to understand the forces preventing the unsupported end of the axle from falling under the influence of gravity, and why the gyroscope would rotate around the post once the free end was allowed to fall, but in fact did not fall. I had previously spent quite some time looking at this weirdness and wondering what was going on. By modeling the gyroscope, which is in fact a simple flywheel, I was trying to reduce the problem as far as possible.
It has occurred to me previously that there must be a force acting on the earth for it to undergo precession. However, just when I thought I had a handle on it I learned that there are two types of precession. Torque-induced and non torque-induced. I've not spent the time to learn the dynamics of non torque-induced precession due to other interests etc. so I let the earth's precession slide on by for the time being. Then I began reading this post and realized my asprin powered pen might have to come back out.
Since I got CFS my job squeezes most of the juice out of my poor little brain cells and they are very reluctant to do anything further. Trying to get them to tackle anything else is about as easy as pushing jelly up a pipe with a toothpick.
Once you introduce a magnetic field of sufficient magnitude to have appreciable affects things become even more complicated. In the case of a metallic gyroscope with an imposed axial magnetic field Lorentz force must be considered. And to make matters worse, that is also an angular force. And then, to complicate it even further, you get another problem at no extra charge. There will then be an angular motion of separated charges which will introduce more magnetic field interactions.
I did discuss the water in a basin problem with Nuske. He believed, as I do these days, that the bowl is not of sufficient scale to be affected by the earths rotation and that bowl design and initial conditions play a larger role. However I say this with great caution as I have not personally done any experiments of my own with this particular model.
Nuske believed the release of the water into the bowel was going to affect the outcome to a large degree and would have to be arranged with great rigor, and the experiment repeated many times over with the same apparatus and initial conditions. Nuske claimed at that time that he had himself done this experiment and that he observed indeterminate results as the water would just as often go either way. I do know that this is done for tourists at some locations, but again, what are the initial conditions? Is the water poured in 'exactly' perpendicular to the axis etc etc.. Has there been sufficient time to allow the water to completely settle such that there are no disturbances whatsoever? I can't know the answer to these questions.
Now, your experiment introduces another consideration Chris. If it is tap water there are ions in the water. These ions will interact with the magnetic field via Lorentz force. If one were to use pure water and the rotation still occurred it is even more complicated, and certainly of interest to me. What affect would the magnetic field have on a non conductive medium that is in perfect charge balance? I am not aware of any forces that the magnetic field could impose on the water under such conditions. However, if I were to list the number of things that I do not know there would not be enough paper, or bytes available to record it. What is even worse is that not only is there virtually infinite stuff that I don't know, but I can't even know that I don't know it until I become aware if it in the first place! Learning, for me, seems to have an inverse relationship to knowledge.