[N320047], Technical Note, Thomas Alva Edison, April 22nd, 1886


View document with UniversalViewer   → View document on Archive.org  → Re-use this digital object via a IIIF manifest


[N320047], Technical Note, Thomas Alva Edison, April 22nd, 1886

Editor's Notes

pp. 47-55 "It is probably that an electric current cannot get the atoms of non magnetic metals completely rotated so N & S are exactly opposite each other. They rotate with [possibly related to pyromagnetic?] difficultly while the iron atoms rotate easily and when a piece of iron is saturated the atoms are all oppposite in polarity ie (drawing) in copper even by a current heated to the metling point they are only partially rotated (drawing) The effect of heat must be to rotate the atom sin the opposite direction as at red heat magnetism is lost, while electric conduction which can only take place by rotation is diminised by heat Now the question is does iron become a better conductor of E if magnetised Try (drawing ) measure it magnetized and demagnetized-- If not there as iron outside of its magnetic property acts to a electric current like another metal then iron must be have a compound atomic arrangement one system of atoms rotating easily gives us magnetism while the regular atoms system causes to act like another metal to E. I must carefully investigate the phenomena connected with the sudden jerk in red hot iron noticed by Barrett, see if it does it without current but by heat alone without Electricity. It may be iron has no magnetic polarization in air hence its how magnetism [perhaps all metals no magnetism but air is polarized by thermo & can't show it?] (drawing) Hence the air seems conduct lines of force Iron several hundred times better than same lines of force from copper etc This would seem to show that there was either a surface polarization of the copper or the end atoms on Iron were rotated exactly north & south with a given current while with other metals there was only partial rotation ie (drawings) If rotation of Copper atom was 1/100 part of that of iron atom with given current the polar pull or attraction at the ends of copper would be only 1/100 part of that of Iron because the total surface of active atom surfaces would only be 1/100-- Iron very probably is fully retarded when saturated. If conduction is rapid occilation of atoms (from the great earth pole line or internal attraction due to earth cutting lines of force from the sun) Then the amplitude is due to the amperes, and rapidity to the number hence a one ampere cell will give a current which will give a certain amplide of axial rotation sya 100 M in second, 2 cells added together & still same current & twice resistance will give same amplitude but twice the number ie 200 M or in the whole length what is probably more current Keep up the same amplide in the first ohm The increased pressures preventing a fall of amplitude in the first ohm by the addition of the second ohms"; p. 57 "If steel is definite combination of carbon and iron, then when cast iron is molten it should decompose with a strong current say 1000 amperes per square inch section (drawing) good!"; p. 59 "Determine by the 39 inch pendulum experiment apparatus if The saturation curve in amperes is the same when the poles are far apart or close together"



Folder/Volume ID


Microfilm ID


Document ID



Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University
Download CSV | JSON