394 
MR DEtrCHAR'S ACCOUKl' 
moves from C towards D, and, when it has nearly arrived 
there, B again moves up, and A descends : and thus, it 
was maintained, the continued motion of the pendulum 
was kept up. 
Another way of exhibiting this deception is shewn in 
lig. 8. Here, by the false account given^ we are told, that 
a very fine steel beam, about an inch in length, has been 
made to revolve with great rapidity fot many months, and 
that two magnets, partially coated with the extraordinary 
black substance already noticed, and placed at opposite 
sides, are the sole cause of the motion. This motion, it is 
almost unnecessary to add, was also induced by secreted 
machinery in the box on which it rested. On one of the 
nights of lecture, when I was upon the subject of magnet- 
ism, this scientific juggler brought his perpetual motion, as 
he called it, to the class-room. As at this time I had the 
largest of the three magnets (fig. 9.) suspended there, for 
the purpose of explaining its peculiarities and powers, I 
thought it would be a good opportunity to try the truth of 
his assertion with regard to the cause of the motion. I 
therefore placed the revolving needle (fig. 8.) on a table 
under the large magnet, while the usual v/eight which it 
carried was removed, but the needle moved as rapidly as 
before. Here, then, a loadstone, capable of lifting 205 
pounds, did not affect a needle, said to be moved by two 
very small artificial horse-shoe magnets. — On another occa- 
sion, I placed a piece of the black substance, which was 
called a non-conductor, between a magnet and a magnetised 
sewing-needle, which I balanced on the point of my finger, 
and I found it to be attracted and repelled, as the different 
poles were presented, in the same way as if no such black 
substance had intervened. 
