For about 700 years, magnetism has been known as the force that stands still. Last week a physicist claimed to have proved that magnetism moves. Professor Felix Ehrenhaft, formerly of Vienna, told the American Physical Society meeting in Manhattan that magnetism flows as electricity flows. If he is right, his discovery is at least as revealing as Benjamin Franklin's kite, and technology has a new horse to harness.
Instead of using cosmic rays or esoteric mathematics for his demonstrations, Professor Ehrenhaft impressed the gathered physicists with little experiments a man can do on his desk with a glass of water, a magnet or two, a compass, some acid and some electric wires:
In acidified water a piece of soft iron sends up bubbles of hydrogen (the metal reacts with the dilute acid and hydrogen is given off). But when the submerged bar was magnetized, Professor Ehrenhaft found oxygen as well as hydrogen bubbles. The only place the oxygen could come from was the water. It seemed that the water decomposed under the influence of the magnet just as water does when an electric current runs through an electrolytic solution. Professor Ehrenhaft argued from this that as no electric current was involved in the experiment, a magnetic current must have done the trick.
When the gas coming from each end of the magnet was analyzed, that from the north pole was found to contain the most oxygen. Professor Ehrenhaft thinks that oxygen "bears a magnetic charge" like the north pole and was therefore repelled. He calls such charged particles "magnetic ions," compares them to electric ions.
The magnet's north pole, he thought, at the same time attracted other magnetic ions having a south charge and the south pole attracted ions with a north charge. The Professor thought that this conclusion was bolstered by a strange finding: when he left a permanent magnet overnight in the weak acid, it lost about 10% of its power (permanent magnets normally lose strength very slowly).
When an electric current flows through a wire it stirs up a magnetic field going around the wire like the brass rings on a Burmese hillwoman's neck. Prof. Ehrenhaft says that, in turn, there is an electric current going around any magnetic field. He places the poles of a magnet one above the other in waterwhereupon small, electrically-charged bubbles go round and round the magnetic field between the poles.
The physicists were enthralled. They heard Prof. Ehrenhaft repeat what they all knew: "Electricity and magnetism represent an indivisible pair." But the phrase had a new meaningfor the first time, magnetism seemed a potentially hard-working partner.