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Show ARC AND INCANDESCENT. r, Tracing, the Mcantifal Ulcctric Iilffht front Its Primitive Condi-J Condi-J -i tion to It Preaent Perfection. BiBili mummm " "!L L- - In .my .opening I letter I spoke of the incandescent light as perfect for the pur-pose pur-pose of .interior , illurnination. A simple :', filament of Jightrglowing in vacu6;dt is 1 the realization of many a studeht's dream, 1 and; rKK'ng guerdon 'for ! the brave bon-' bon-' tes'tants'who, undismayed by. ail,ure, peH aistently denied ' the insurmountability of obstacles-believers, alsb,; in tlie grand old : doctrine that : those who work must Watching in mymirid's eye ) the Progress Pro-gress of 1 . the : electric . -.light, the, ever-recurring ever-recurring contretemps to which investi-! gators were -subjected as, viewed iri the j fight of the present day are' simply amts-,J ing.' Breaks in wire insulation, difficulty j in' adjusting the battery power , to', the ; needed force, inability to preserve-the ' correct adjustment of carbon points pro- ! voking intervals of total darkness alter- j riatihg with ' short periods of: brilliant j h'ght, difficulty :.ever recurring, all-per- j vading,' seemed to be the heritage of the . seeker. after light.,,'. : , :J- . ' '.. !,Now, the induction of electric currents j and,, the .cpllectioh and storage of the i force are matters' of. ease and . certainty. Its value as an illuminant in relation to other standard -.lights . is ascertained, its volume can he measured and the iorce itself can '., be , accumulated . in portable . storage batteries, jand .transported, from place to plaice with a very small percentage percent-age .of Ipss. dwellings, may be - lighted from basement to . atSc, ov. simplv . con necting the" wires with a portable ,ac cumulator, turning a switch, or pushing a button j and the operation ' is complete. Every h'ght m'a be under seperate coh-trol, coh-trol, and the yblnme of light in any lamp may be increased or diminished " with as mrlch facility as if gas were the illuminating illumina-ting agent;-"The device which renders all this-, possible is the dynamo machine. The foundation principle of the dynamo was discovered by Farady as early as the year 1831, and forty-six years later is the date of Brush's first patent for the inost j popular dynamo at present known to us. : In the early days 6f electrical experimental experi-mental research, the ; electric ' fluid or force was generated by the 'ordinary Voltaic Vol-taic battery; consisting of two plates of zinc and copper partially ' plunged iri a bath of acidulated water,-a .wire being I connected with each plate, and the union i of the two wires forming a circuit.. But it ! was evident from the beginning that in j order to obtain a. sufficient volume, of j electric" energy or force for the purpose of I niumiriatlfin somft othftr mfann mnat ha devised for its production, more, constant in result than ordinary chemical action, and at a greatly lessened cost in order to make it commercially available, ; I have stated that Prof. Farady laid the foundation founda-tion ort which all dynamos ; are constructed, con-structed, . .and . his dicovery, simply was, that when a permanent magnet is placed in close proximity .to a coil of copper wire, "and either the magnet or the coil is made to revolve at a high velocity a current cur-rent of electricity is induced ; and following follow-ing up this important result machines were constructed called dynamos, for the purpose of generating the electric energy. The electric energy so induced is collected by ' various devices, and is either conducted con-ducted into immediate service) or . is turned into the storage battery and laid up for future use. The Brush dynamo when in operation is asight well worth seeing by any person interested in mechanical me-chanical or scientific matters. The heavv castings and bright metal work,' the light wjampirig,flashihg, dancing the steady humming cadence of : the machine, proclaiming pro-claiming to the educated ear . the perfection perfec-tion of mechanical adjustment, are apt to leave a mental impression of entrancing uncanniness. !i Such is the" dynamo or generator. 1 1 have said that the electric fluid may either be conducted to the lamps direct or be carried to a storage battery, arid there kept for future use. A very cursory examination of the subject is sufficient to show that incandescent I lighting direct from the dynamo has serious ser-ious disadvantages, such as ' irregularity of pressure Or a total cessation of light, I whenever either from accident or neces- ! sity trie dynamo was at rest, and as incandescence in-candescence is the light of our homes and places of business and assembly, the chance of being left in darkness without possibility of avoidance would be fatal to its claims as a practical illuminator. " In this: dilemma tlie 'accumulator or storage battery c'oiries ' into"' play a box j of convenient size ' for handling, divided , into cells, each cell containing plates of lead in an acidulated bath. ' Wheri the cells in. the. accumulators, are charged with electricity from the dynamo chemical chemi-cal action is set up, and : certain radical changes in the constituents of the battery bat-tery are affected, leaving the contents apparently ap-parently dormant, but whenever an electric elec-tric circuit is established a reaction takes place which reverses the prfiriary process set up wnen the battery, was eing; primarily prim-arily -charged, and in the course of reversal re-versal a volume of electricity is gradually given out, equal to about ninety per cent Of the electricity, with which the accarnu-lator accarnu-lator had been charged by the dynamo or storage battery. By its use a steady supply ot electricity may. be secured by a given number of "lights, burning a stated number of 1 hours, under perfect control regular measurement of electric force consumed, cut off, and regulation of indi vidual lights, and with practical freedom from wastage.dnnng periods of non-combustion ;so that while the dynamo is an I all-sufficient producer, the storage battery bat-tery is an equally all-sufficient retainer and dispenser of the force or fluid . so produced. , .-. .., " . . ,. , . The incandescent light is the antithesis Of the arc m some of its primary and es- i r"-1!,10.118-' The carbons in the f arc lights burn in atmospheric air. are in-tersely in-tersely heated, conductm and complet- mg the electric circuit between the car- ! Wh -latter are : rapidly disinte- : grated... The incandescent light burns in" vacuo, anything but-the merest trace of ; oxygen being fatal to its continuity Ac- ! cordinfftn WfMa , J. . L tn - no ciecinc resistance to cdrbon is about . two hundred and fifty times greater than that of platinum, and its temperature may be .raised without any danger of fusion ; moreover, arbon imsiit an equaf temperature a greater radiating ra-diating heat than platinum, so that the same amount of heat raises a carbon P,nt, a mu.ch higher temperature thanl a plabnbM .wirel !The carbVns for electric elec-tric lighting are made exclusively from ' enthghting bemg suny filaments of vi ef able matter twisted Into Variour8haDes -ZtaS. t?? as ofTifferent fn! "uu, navmg the two ends fastened to platinum wires, the hes sealed into the Jieck of a glass bulb bv an air-tight jomtand the air exhausted nlX I" Ulb' tWSt an end Jn tote pUtantrm-wjres,.' andfthe Wn ia the positive and negative wires of a w. tery are conducted, the end of each w?re bent into the shape of a hook wi Vi top of the holdeTfitted -S' I i th, spring, place the lamp on a sprint T ! downward until tb eyesoo tG JL&Z wires are connected with the the, battery wires, and you haw n descent light in circuited wh11" electric current is establUW .tver ari the lamp theTarbon mS,Stliroi? a white heat and emlSTfe . grateful light, the absence of 5 P venting combustion or disintegration ot the carbon filament, rendering its hghtj, 1 barring accidental breakage, sufficiently. . long for all practical purposes. : , A. C. N. Howard. |