TO THE MOVEMENT OF MACHINES. 507 
points,and is not at all affected by their relative velocity. The inversion 
of the poles being effected instantaneously, we should thus have a velocity 
infinitely accelerated. Now asystem moving round an axis, and capable 
of a continuous circular motion, is that whichis alone susceptible of such 
avelocity. It cannot become uniform, unless some resisting element, or 
some other action depending on the velocity, is introduced into the 
system. Putting aside the application to practical use which has to be 
made of such an apparatus, the obstacles to be overcome, inseparable from 
the system, consist only in the friction of the pivots in the sockets, and 
in the resistance of the air. As to the former, repeated experiments 
have proved that the friction is independent of the rapidity of rotation, 
at least within the limits of experiment; this resistance, therefore, can 
in no way contribute to render the accelerated motion uniform. It 
is in fact the resistance of the air which will act to produce this effect. 
Although it might be reduced at pleasure, principally by giving a suitable 
form to the rotatory system, it would not be entirely annihilated. But it 
willbe allowed, that weshould have reason to be well satisfied with the me- 
chanical effect of magnetism, if this were the only cause which tended to 
reduce the accelerated movement to a uniform movement. The limits of 
such a uniform velocity must be very distant. I do not speak of the great 
simplicity of a magnetic machine with a continuous circular motion, of 
theadvantages of construction which are gained by being able to trans- 
form with ease this motion to any other which the working machine 
mayrequire. These considerations hadstrongly impressed my mind, even 
whilst the means of execution were still unknown to me, but I always 
kept in sight the practical application, and the object appeared too 
important for me to exhaust my powers in the construction of see-saw 
toys, which might claim the honour of being placed in the rank with the 
electric chime relatively to their effect, and still more relatively | to the 
tinkling with which they are accompanied. 
4. 
Fig. 1. of the annexed plate represents the magnetic apparatus of eight 
bars, arranged symmetrically upon a disc moveable round the axis A, and 
of eight fixed bars similarly arranged uponafixed platform. 'The arrange- 
ment of the bars admits of the greatest variety, provided it be exactly 
symmetrical, and that it allow the poles to approach each other as nearly 
as possible. To prevent the action being too oblique,—since the centre 
of magnetic gravity is probably at some distance from the extremity, as 
in the ordinary magnetic bars,—it is preferable to make this arrangement 
so that the axes of the cylindrical bars shall be situated rectangularly, 
and not parallel, as in the figure. It must be further observed, that there 
will be some difficulty in forging bars of considerable dimensions into 
the horseshoe form, so that the axes of the branches be situated exactly 
