TO THE MOVEMENT OF MACHINES. 505 
2. 
In May 1834I constructed the first magnetic apparatus with a pri- 
mitive continuous circular motion. It is true that, like M. dal Negro, 
(with whose labours I regret that I am not better acquainted,) I had 
several years ago conceived the idea of applying this power to mecha- 
nies: but I could not at first divest myself of the idea of making this 
application by means of an advancing and receding motion, produced 
by the attractive and repulsive power of magnetic bars,—a motion which, 
by known means, might have been changed into a continuous circular 
one. It seemed to me that an apparatus of this kind would have 
only the merit of an amusing toy, which might find a place in the eabi- 
nets of men of science, but would be entirely inapplicable on a large 
scale with any advantage. 
For considering the general equation of active forces applied to the 
movement of machines 
=f Mds — 2" Pds' = Emv, — Emr, 
the magnetic action, during the amplitude a, and represented by 
be “Md s, could not be perfectly exhausted by the action = if Pd 2 
os the active foree gained during the movement repeat Zero, 
orlm ope Zmv. =0. Now the magnetic attraction is a function of 
the space, the form of which we do not sufficiently know, this function 
being affected by the nature of the distribution of the magnetism in the 
body, of whatever form. The law of this distribution is scarcely esta- 
blished with regard to bars of steel of a regular form, magnetized to 
saturation and deprived of consecutive points. With regard to bars of 
soft iron of considerable dimensions, magnetized by an electro-con- 
ductive helix, we have analogies only, but no experiments. But however 
this may be, we know well that this function must be expressed by a very 
convergent series, so that the magnetic attraction will be in an inverse 
proportion to the square or to he. cube of the distance, or, stopping at 
the three first members, will perhaps be composed of them. The mag- 
netic points then approach each other with an accelerated motion; the 
active forces increase, and reach their maximum at the instant when the 
contact is completed: but this force ought then to be destroyed. It 
will destroy itself by the fixed points of the machine, and by the vibra- 
tion of the system: but this will be in an unprofitable manner. There 
2 2 
will be a complete loss of theactive force obtained 2mv, — Xmv. We 
o 
know the ill effects of shocks in the movement of machines, but there is 
here another inconvenience which is not simply mechanical. The soft 
iron, by these repeated shocks and vibrations, gradually acquires at the 
