Page:The American Cyclopædia (1879) Volume XI.djvu/22

 14 MAGNETO-ELECTRICITY ami improve.! l.y Kulunkorff of Paris, and was Mill further jii-rfi-rti-d by an ingenious Ameri- FKJ. 1. Lighthouse Machine. can artisan, E. S. Ritchie of Boston. The es- sential desideratum in the construction of this instrument is the perfect insulation of the sev- eral spires of wire, so that the intense electricity which is pro- duced may not strike across from one spire to another ; and Mr. Ritchie effected this by means of an ingenious process of winding, together with an improved insulation. An ap- preciable time is required to overcome the resistance of the wire and to give it a full charge of the current of electricity, and also to magnetize iron ; hence in the instrument we have described, when a single battery is employed, the in- duced current, which gives the intense spark, is that which is produced at the rupture of the battery current. We can how- increase the intensity at tin- he-inning of the current, ly employing a battery of a number of elements, which, producing electricity of greater intensity, more suddenly estab- lishes the current in the wire, and more rapidly develops the magnetism of the iron. The improvements that have been made of late in the construc- tion of magneto-electric or in- dootion machines have been so iMUngattO warrant the hope -hall eventually derive great advan- tages from the powerful electric currents that h* I Ar can thus be instantaneously generated, produ- cing light, heat, or other effects in any locality whither the conducting wires are led. The ac- companying figures il- lustrate the forms of the most notable machines that have been con- structed. The first is the machine construct- ed by the compagnie cfalliance of Paris on the plans of Clarke and Nollet. In Clarke's ma- chine, which is but a slight modification of Saxton's, two soft iron cores, connected by cop- per and iron bars, re- volve rapidly in front of the poles of a power- ful horse-shoe magnet. Around these cores is coiled an insulated cop- per wire, whose ends are so connected with a "commutator" that the alternating currents of electricity circulate always in the same direction through the exter- nal circuit. In the machines of the Alliance company the use of the commutator may be FIG. 8. Wilde's Machine. omitted if the currents are designed only for the production of light, since in this case the rapid reversals of the current are an advantage. In bieraens's machine, fig. 2, invented in 1854, a