280 llev. Mr Scorcsby on some of the Laws 



small ; but with three-feet magnets it may be supported more 

 than a quarter of an inch below them, so as to admit of plates 

 of glass, metal, or thin wood, to be passed between. A key, 

 weighing 580 grains, has been supported by my own three-feet 

 magnets witliout contact. 



If two keys or wires be suspended contiguously at the same 

 time, they will repel each other, and if a small magnet be brought 

 near them they may be attracted, repelled, or agitated, to a con- 

 siderable limit. 



Modifications of the experiment are represented at b, c, d, e, 

 f. A small piece of tinned iron is suspended at b ; at c, two 

 pieces of iron- wire ; at d a crooked piece of wire * ; at ^ a small 

 kite covered with silver paper, with a piece of wire in the mid- 

 dle; atya balloon, formed out of an egg-shell, reduced to ex- 

 treme thinness in vinegar, and coloured. An axis of iron-wire 

 yields the requisite suspensive energy. 



The story of the suspension of Mahomet's coffin within a 

 loadstone cave is amusingly illustrated by this experiment. 



Series B. 



With a compound horse-shoe magnet and an iron-bar, or single 



bar-magnet, for partially neutralizing one of its poles. 



All the experiments of the preceding series can be equally 

 well performed with a good compound horse-shoe magnet, ac- 

 cording to the arrangement represented in PI. IV. Fig. 12. 



The magnet being suspended from a frame of wood, is so ad- 

 justed in height that one of its poles should rest upon a large 

 flat bar of iron, or else upon the end of a bar-magnet with op- 

 posite poles coincident. By this means the pole in contact with 

 the flat bar is partially neutralized, so that the operation of the 

 unattached pole is left more free and unembarrassed for the per- 

 formance of the experiments. 



It is not necessary to repeat here the series of experiments 

 with this apparatus, being precisely similar to those under the 

 preceding arrangement. *" 



* This wire, weighing 18 grains, was suspended by the pair of three-feet 

 bars, at the distance of three-eighths of an inch below. In performing this 

 experiment, in any of its modifications, it will be found advantageous to em- 

 ploy a very short thread, otherwise its elasticity will prove inconvenient, if 

 not fatal, to the success of the experiment. 



