384 M. J. Nicklés on a New System of Hlectro-magnets. 
I will now add more data to complete my former communica- 
tion. By its properties this electro-magnet calls to mind the 
magnets ‘a points conséquents,” its middle pole being much 
stronger than the two outer. 
With this magnet we may obtain a rectilinear motion, which 
I have in fact found to be true, though in a less degree, with the 
ordinary magnets. Ihave stated in my preceding note that the 
two lateral arms of the new magnet are larger than the middle 
arm. On placing a cylinder of iron at the origin of the arms 
perpendicular to their direction, this cylinder rolls with great force 
towards the centre of the magnet, and returns as often as it 1s 
put back to its first position. This movement back and forth, 
which may be increased in extent, takes place, whatever the po- 
sition of the apparatus, or inclination of the poles. 
This movement appears to deserve some attention, for it ena- 
bles us to construct electro-magnetic machines in which the mag- 
nets act in contact, without producing a shock; for it is well 
known that with the ordinary machines, the shocks when the 
magnets touch deteriorate rapidly the power of the machine. 
The table below gives the force of attraction exerted by these 
Magnets with currents of different intensities. ‘The armature here 
used has the size of the central arm; it weighs 1030 grammes; 
and its rectangular form adapts it well for the experiments, 
since it may be made to touch by the small or long side, in aa 
axial or equatorial direction, according as it may be desired to act 
With one, two or three poles; and finally, by using the Jarge sur 
face, the magnetic radiation may be almost entirely intercepted, 
and we may thus obtain the weights lifted as given in the 4t 
column. 
The total current of the battery was tan. 56° 25’; the reduc- 
tion observed when the helix was in the circuit, tan. 49° 55 
The different intensities were ascertained by means of a rheostat. 
3 Poles. 
Armature presented Armature presented 
Current. Middle pole. 2 Poles. by its edge. by its large § 
Tan. 49°55’ = Skil. ~—- 80 kil. 130 kil. 180 kil. 
46°10 = 2 68 120 142 
14° 45) 6 15 142 
oe AY 30 3 4 142 
~ With an armature of different form these relations are changes 
thus a ru iron, Om: ong, 0™-02 broad, an 0 al 
oy ce the ratio of $ between the weigh PE lite 
y the middle pole and the three polar surfaces united. 
drical.; aaaeeee et given analogous 
of 0-015 section, have 
results. eal 
