The Montgomery advertiser., 1901-08-23

" Supply malS.1dl TOT q tWO-cOlumn article. The real difficulty IS. rather, to compress the subject matter into so small a space.
 Some metals possess fairly high cleo trical resistance; iron and platinum have only one-siXth the conductivity of copper; both have been used in early lamps. but iron has too low a fusing point emitting only a red light, and platinum is too expensive; they require relatively large currents 10 heat tLem, and the high temper ature quickly ruins their structure. Professor Farmer | once lighted his house in Salem, Mass, by platinum lamps operated om pri- | mary batteries; they were connected in series on one circuit and ,nclosed in | glass globes to reduce oXid .zation and | to conrne melted particles. As lateas | 1878 Edison constructed such lamps with automatic devices to shut off the current in case of ruinously high tenn perature. In 1879 Swan in England and Edison in this country independ- ently made lamps with carbon fila ments in vacuous globes. This mate rial has proved eminently suitable for the purpose and its adoption marks the beginning of commercial incandescent | lighting. Various substances have been | employed for producing the carbon cotton and silk threads at first; strays. lbank note paper, bamboo fiber and Hastily cellulose.
 The gain by use of carbon was mo- table and decisive; this substance has 2,500 times the resistance of copper; therefore, current that can be driven a long distance through copper wire wit thout serious loss of energy will suf- | flee to heat the filamantS of large number of lamps. Further, the small current required by each lamp made practicable the operation of them In | multiple-that is, two parallel wires could be attached to the dynamos ana I each lamp connected across, lndepend- ent of the others, resulting Tn nlul- tiplicity of paths; the current that fows through one lamp does not flow through the others, Previous to Edison's dis covery no one thought of connecting several devices of any Kind Tn any other manner than series. When 1t was announced in London that Edison hau discovered a method of subdiVldlnS the electric current gas stocks LOOK sud den decline.
 Between invention ana cornniercld, | article may elapse several years ana Inc exnenditure of thousands of dol lars. The history of incandescent lamps is no exception and the manu- facture of them is an art refined alike hv scientific knowledge and skilled workmanship. Even at this late day there are many persons who suppose the slender filaments are made or metal, and the construction of the lamps an offhand matter. In reality the construction of watch demands no higher degree of accuracy; while the parts of a watch are actually de- terminei by use of automatic machi- nery, each lamp in its fifty separate operations and forty inspections is the result of calculation, manipulation and judgment.
 As the particular processes of manu- facture are constantly being changed and improved, some operations pro- tected by patents, others by secrets, no completely up-to-date description Of what might he seen in lamp factory can be given. Millions of lamps of one general style have been made and
 many still in use; a brief account of
 the successive stages in their construc-
 ton can be of interest.
 Close straight grained sticks or oam- boo are cut In pieces about six inches long, then split into as slender shreads as possible. and made ok uniform size
 by being drawn through successively smaller holes in steel dies; the particu-
 lar lengths and diameters are deter mined by considerations of the candle w.l