1866. | Wilde's Magneto-electric Machine. 507 
conditions of the atmosphere, by placing small blocks of iron on the 
top of the small magnet cylinder b b, so as to connect the opposite 
poles, and proportionately diminish the power of the induced 
current in the armature. 
This machine is, as already mentioned, considerably smaller than 
the one now in existence. In the former there are only two con- 
versions, that is to say, a permanent magnet—an induced current 
of electricity—an electro-magnet—a more powerful induced current. 
In the large machine there is a still further multiplication of force. 
Its small magneto-electric machine has an armature of 13-inch 
diameter, armed with six small permanent magnets weighing | |b. 
each. The induced current from this is transmitted through the 
coils of the electro-magnet of a 5-inch* electro-magnetic machine, 
and the direct current from the latter is simultaneously, and in like 
manner, transmitted through the coils of the electro-magnet of a 
10-inch machine. The weight of the electro-magnet of the 10-inch 
machine is nearly three tons, and the total weight of the instrument 
is about 44 tons. The machine is furnished with two armatures— 
one for the production of “intensity” and the other for the pro- 
duction of “quantity” effects. ‘The intensity armature is coiled 
with an insulated conductor, consisting of a bundle of thirteen 
No. 11 copper wires, each 0°125 of an inch in diameter ; the coil 
is 376 feet in length, and weighs 232 lbs. The quantity armature 
is enveloped with the folds of an insulated copper-plate conductor 
67 feet in length, the weight of which is 344 Ibs. 
With the three armatures driven at a uniform velocity of 1,500 
revolutions per minute, an amount of magnetic force is developed in 
the large electro-magnet far exceeding anything which has hitherto 
been produced, accompanied by the evolution of an amount of 
dynamic electricity from the quantity armature, so enormous as to 
melt pieces of cylindrical iron rod fifteen inches in length and fully 
one quarter of an inch in diameter, and pieces of copper wire of 
the same length and one-eighth of an inch in diameter. With this 
armature in, the physiological effects of the current can be borne 
without inconvenience ; immediately after fifteen inches of iron bar 
had been melted, the writer grasped the terminals, one in each 
hand, and sustained the full force of the current. The shocks were 
certainly severe, but not inconveniently so. 
When the intensity armature was placed in the 7-inch magnet 
cylinder, the electricity melted 7 feet of No. 16 iron wire, and made 
a length of 21 feet of the same wire red-hot. The illuminating 
power of the current from this armature was of the most splendid 
description. When an electric lamp, furnished with rods of gas carbon 
half-an-inch square, was placed at the top of a lofty building, the light 
* For the sake of convenience, the different sized macliines are distinguished by 
the calibre or bore of the magnet cylinders. 
VOL. II. 2 M 
