144 
Proceedings of the Royal Society 
by causing the armature to do work, the magnetic attraction will not 
act, and this amount of work will speedily stop the rotation of the 
armature. It is also clear that if the armature be not revolving in 
synchronism, and be doing no appreciable work, the magnetic attrac- 
tions will always be tending to bring it more nearly to synchronism. 
These conclusions are all in accordance with what I observed. 
This is all that I have done as yet in an experimental way on the 
transmission of power by alternate currents. It is easy to follow 
out the results which must follow when a machine with a Pacinotti 
collector (or commutator) is used, or when a magneto-electric motor 
is employed. But I will not enter on this subject until I have 
experimental data to support these conclusions. 
I have considered these results, small as they may appear, to be 
worthy of the attention of this Society, because of the great value 
which I attach to the transmission of perfect synchronism. It is 
well known that in the construction of motors a great deal of 
ingenuity? has been expended in endeavouring to obtain a stead}^ 
speed, while the motor is doing a variable quantity of work. This 
difficulty is completely overcome by the use of alternate currents. 
It is true that the efficiency of my motor was small, owing to 
the feeble magnetism of the field magnets ; but perhaps this can be 
overcome. I have said that the motor I used was one of the well- 
known Griscom motors, and the current I used was IJ ampm’es, 
measured by a Siemens dynamometer. From an exceedingly rough 
estimate of the pressure on the pulley which was required to stop the 
motor, and the surface velocity of the pulley, I believe that I 
obtained about 200 ft. lbs. per minute. 
But it is not the regularity of speed of motors which strikes me 
as important so much as the power to transmit absolute synchronism 
to a distance. It is, of course, well known that the main feature of 
many telegraph systems is “ synclironous action.” This is the case 
with the Hughes printing telegraph, so unfortunately neglected in 
this alone of all-important European countries. So it is with the 
Baudot and other modifications of the Hughes, and still more so is 
it the case with the autograph systems of Caselli, D’Arlingcourt, and 
others. 
