a?id Phenomena of Magnetic Induction. S79 



ployed in these experiments should be highly poh'shed, and, to 

 obtain tlie best effects, the iron of which they are composed 

 should be annealed or softened previous to the polishing. 



(2) — Fig. 8. a, PI. III. exhibits another modification of the 

 experiment, in which a half link of iron-wire, 6, similar to the 

 former in thickness and quality, is appended to each extremity 

 of the crossed wires, and the balls are now suspended from every 

 point. Each of these, without the interposed iron, will sustain 

 from two to ten or more balls, according to the power of the 

 magnets. 



(8.)- — An elegant variety in this experiment is obtained, un- 

 der powerful magnets, by adding to the half links suspended from 

 the cross wires, a second half link to the extremity of each of 

 the first series ; and, even at this distance from the magnets, a 

 chain of six graduated balls (see Fig. 9.)? may be suspended 

 from each of the sixteen downward terminations of the last series 

 of wires. 



But these three last experiments admit, of course, of an unli- 

 mited variety of modifications. 



Experiment 3. — Formation of Chains of Half Linl's. 



A pair of good twelve-inch magnets will sustain a chain of 

 about six half links, of the size of wire above described, which 

 may be increased to five full links, measuring above nine inches 

 in length, by the use of the three-feet magnets. Fig. 10, a. 



This experiment is modified, as represented at b, by the in- 

 terposition of a ball between each complete link ; at c, by a ball 

 at each limb of the half links ; at d, by the introduction of 

 the crooked wire. Fig. 7. b, &c. ; and at e, by a weight of cork 

 suspended from the fourth complete link. 



Experiment 4. — For Suspension, without contact., of Small 

 Masses of Iron. 



This is a very striking and curious experiment. Fig. 11. a, 

 represents the general arrangement.* A very little key held 

 down to the table by a piece of fine thread, or a hair, is brought 

 within a small distance of the extremity of the magnets, where, 

 the thread being on the stretch, it can be suspended without 

 contact, quivering in the air. With twelve-inch magnets, the 

 distance at which the key can be sustained will be exceedingly 



