1868 document signed Rowland and witnessed in 1869 three female Rowland's. He was twenty years old and Gramme had just demonstrated his improved machine with self-excitation.
MY FIRST SHOT AT READING THE HANDWRITTEN DOCUMENT. If you want to see the figures you can find the document in the archives of Johns Hopkins.
John Hopkins University Files
"The old arrangement (figure IV) of a revolving armature is subject to much objection as will be explained here after. I would suggest the employment of a machine made after (figure I) in which the wire (b) revolves around a stationary armature (a). It is well known that only a small percent of the power is converted into electricity in the machines shown in figure IV which may be considered as the types of all the machines now used.
Now there is very little reason to doubt that when a single wire is made to cut the lines of a magnetic force, that the whole of the power is turned into electricity. Now in what does the later inferrment differ from the magneto-electric machine? Simply in the now-employment of an armature. We must look with suspicion to the revolving armature for an account of this waste of power. There are two causes for this resistance to the rotation of the armature: first, that due to it as a conductor of electricity and second as a magnetic metal.
1st As a conductor. It has been shown by Faraday that when a piece of copper is suspended between the poles of an electromagnetic as shown in figure V, if it is spinning around, it will be instantly stopped when the magnet is magnetized. It is evident that this same action will take place in the electro-magnetic machine. This action arises from the induction in the piece of copper or the armature. These are represented in figure VI. The currents will tend to make the pole revolve as seen in figure VII which will cause a resistance and consequently a loss of power.
2nd As a Magnetic metal. It is well known that iron requires time to become magnetized. This is another source of the loss of power. You, let figure VIII be a revolving cylinder; then since the iron requires time to become magnetized and de-magnetized, the induced poles which are at rest, are at N and S, are carried, as it were, thus causing a resistance to the rotation. The same result can be arrived at in another manner. Grove has shown that when iron is rapidly magnetized and de-magnetized it becomes heated. This is the case of the revolving armature: therefore it becomes warmed: Now we know this heat must come from somewhere, as this is the law of conservation of force; and so we conclude that an equivalent of work has been transformed into this heat.
The form of the machine seen in figure I obviates both these losses of power by (dispersing) with the revolving armature. The coils of wire alone revolve thus cutting the lines of magnetic force and producing the current. There is another advantage resulting for this form: it is that there is an almost constant current from it owing to the fact that some of the wire is constantly cutting the lines of magnetic force.
It might be objected that, as, the power of an electro-magnet does not obtain its maximum until the armature is in its place, so the magnet in this case will not be so powerful as when the figure VI armature is used. I admit this is true to a certain extent when the armature is at rest, but when it revolves the magnetic condition is changed because it remains in no place long enough to become thoroughly magnetized.
I would advise the employment of poles of the shape of figure IX with the machine like figure I. This would admit, if I may so express it, more surface for the conduction (?) of the magnetism of lines of magnetic force through the non-conductor air.