(from the 1842 edition of the Manual of Magnetism, pp 110-111)

Source:

http://physics.kenyon.edu/EarlyApparatus/Daniel_Davis_Apparatus/Revolving_Armature_Engine/Revolving_Armature_Engine.html

If you are at all interested in Ed Leedskalnin's experimental work with magnets and electricity then Im sure you will enjoy reading this Davis's Manual of Magnetism .

There are some fantasic Illustrations in here and some really good experiments.

Book as online PDF

I recently discovered Barlow's Wheel and had to share it with you. It reminds me so much of Ed's experimenting with U shape magnets.

And to further add, Peter Barlow (born 1776) published mathematical books that were regularly reprinted until 1965 , when computers rendered them obsolete.

He made an important contribution to astronomy by inventing the Barlow Lens. Peter Barlow was awarded a medal for correcting a deviation in ship mounted compasses caused by iron in the hull of these ships. Also see Balrow's Law also see Samuel Hunter Cristie.

Barlow made several contributions to the theory of the strength of materials.

Barlow's Wheel is the name given to an early demonstration of a homopolar motor, designed and built by English mathematician and physicist, Peter Barlow in 1822

Source:

http://physics.kenyon.edu/EarlyApparatus/Titlepage/Davis.html

http://en.wikipedia.org/wiki/Barlow's_Wheel

http://physics.kenyon.edu/EarlyApparatus/Daniel_Davis_Apparatus/Barlows_Wheel/Barlows_Wheel.html

These images of 40 um x 25 um in size were obtained by sequential MFM scans after each current pulse. The motion of the walls is best seen by noting the relative displacement with respect to the fixed topographical defects (white dots). The displacement of Bloch walls as far as 200 um along the strip was observed. The direction of domain wall motion was in the same direction with the electron flow, i.e. opposite to the current direction. The displacement per pulse was dependent on the sample thickness and current density. In general, wall displacement occurs when a critical current density on the order of 1011A/m2 is reached. This experiment clearly demonstrate the feasibility of using short current pulses as control signals to alter magnetization of a specific area of the surface.

source: http://www.ece.umd.edu/~rdgomez/Animation1.html

As you can see in the diagram earths magnetic pole in movement over time.

Seeing this old electrical generator reminded me of some of Ed's old workshop, flywheel.
source: http://travel.webshots.com/photo/1082714154047522195YUnrEi

Sound controlled CGI and 3D composition.

Scientists from NASA's Space Sciences Laboratory have made them visible as "animated photographs," using sound-controlled CGI and 3D compositing. It makes the fields, as explained by the scientists, dance in an absolutely gorgeous movie called Magnetic Movie. You don't want to miss this one, which is the coolest video that you'll see all week, guaranteed. You can't argue with a combo of beautiful effects and amazing science.


Source : http://gizmodo.com/5012347/nasa-scientists-make-magnetic-fields-visible-beautiful