Configurations formed ly Floating Magnets. 107 



of a pair of pliers, and with a pair of cutting-pliers snap oft' 

 the needle close to the jaws of the other pliers. Thus form a 

 series of magnets about f inch in length. Run each of these 

 through a thin section of a small cork, and then coat both 

 needle and cork with shellac varnish. Float these magnets in 

 a glass tank placed over the condensing lens of a vertical - 

 lantern ; or you may even float them directly on the condenser 

 itself if this" is made of an inverted glass shade filled with 

 water. This form of condenser was first used by Dr. R. M. 

 Ferguson, of Edinburgh. 



Fio-ure 1 shows the arrangement of the experiment. The 

 ravs of light, R, from a heliostat, or from an oxyhydrogen light, 



fall on an inclined mirror, A, placed under the water con- 

 denser, C. The needles float on the surface of the water in 

 this condenser. The rays which have passed through the lens, 

 L, are reflected by the swinging mirror, B, to the distant 

 screen, where they form the images of the floating magnets. 

 The magnet is held over the needles at M by means of a wire 

 which is wrapped round the magnet to serve as a handle. If 

 a long magnet be used, it will work well if its pole is brought 

 over the needles* by inclining it. 



These experiments with floating magnets give forcible pre- 

 sentations of the reign of law. It is indeed quite impressive 

 to see order being evolved out of chaos as we hold a magnet 



* The magnetic needles in the experiments may be replaced by pieces 

 of soft iron ^ire, which will be magnetized by the induction of the super- 

 posed magnet. 



