S? , > ' V/ ' ’L r ^ P - - ^ ■ * Ig ifinJfnigifuDf fugfiuDfiuflf^ff^ H 4^7 ? 7 ^ (:/M4i6^ n THE LIBRARIES 1“ 02^f6 fg 19 od COLUMBIA UNIVERSITY i Avery Library . Y [g [Uijfnni nugffijarfmlf^ E] 1 •r- - * I * I Ir . ^ *t! .' H JN preparing this catalogue we have endeavored to include information which will en- able customers to intelligently select the lamp best suited to particular requirements. ** The opening section is, therefore, devoted to the manufacture, selection and proper use of lamps, and we believe it will repay care- ful perusal. Descriptions and illustrations of the various types of our lamps, including standard, special and miniature lamps, arc given in the following pages, and the appended general lamp data should prove valuable. We invite correspondence re- garding special lamps of any type, which we arc prepared to manu- facture to order. For the convenience of our patrons, large and varied stocks of lamps arc carried in the follow- ing cities: Lamp Factory, Harrison, N. J. Atlanta, Ga. Boston, Mass. Chicago, III. Cincinnati, O. Denver, Col. San Francisco,CaI, Digitized by the Internet Archive in 2017 with funding from Columbia University Libraries https://archive.org/details/edisonincandesceOOgene EDISON INCANDESCENT ^ LAMPS ^ iV GENERAL ELECTRIC COMPANY Principal Offices, Schenectady, N. Y. Mjin Lamp Sales Office*, Harrison, N. J» FEB. 26, 1900 NUMBER 1028 J THE INCANDESCENT LAMP IS THE VERY SOUL. THE ESSENCE OF ELECTRIC LIGHT- ING, AROUND WHICH ALL OTHER DETAILS OF CURRENT PRO- DUCTION REVOLVE AS SATELLITES TO A CENTRAL SUN.' STAIRWAY IN THE CONGRESSIONAL LIBRARY AT WASHINGTON, D. C THE MANUFACTURE OF INCANDESCENT LAMPS LTIIOUGH an [^incandescent lamp is apparently a very simple device, its manufacture involves many complex pro- cesses. In addition to the mechanical problems, various chemical, electrical, and physi- cal questions must be solved in its construction. In no other manufacturing enter- ]M'ise is success so deqrendent on experience combined with careful, systematic inspection and testing; for apparently in- significant changes in methods produce marked results and the cause of defects is there- fore difficult to locate and remedy. Many jiersons are sur- pri.sed when told that fifty constructive operations and forty separate tests and m- A Tiffany Candelabra . r i i spcctions arc pciTormea by the (ieneral Mlectric Company upon every lamp to complete it for the market. To jiroduce an incandescent lamp, and sell it at our present low price, without omitting any detail of 6 GENERAL ELECTRIC COMPANY manufacture or tests, is an achievement rendered pos- sible only by our enormous output and many years of experience. The bidison lamp represents the most extended exjierience and the largest production, and therefore stands unrivaled. Correct and uniform rating in candle-power by ac- curate standards has always been the distinguishing feature of the Edison lamiv CANDLE-POWER RATING ,,,, ^ 1 he common practice of over-rating lamps or of shipping lamps varying widely in both candle-power and watts is never permitted with Edison lamps. The eye can make only a vague approximation of a lainji’s candle-power, and a customer not proxdded with a photometer is therefore easily deceived. Unreliable manufacturers sometimes take advantage of this fact to supply lamps o\'er-rated in candle-power and therefore in economy. A true i6 candle-power lamp consuming 50 watts has an economy of 3.1 watts per candle; but if it be a 13 candle-power lamp marked 16 candle-power, its economy is really 3.8 watts per candle. Lack of uniformity in both candle-power and watt ratings of lamps is an evil which is frequently charac- teristic of the product of the small and incompetent manufacturer. \"ariation in candle-power produces disa- greeable contrasts in VARIATION IN CANDLE-POWER the illumination, and lack of uniformity in the wattage produces irregular meter bills — both sources of dissatisfaction to customers. An examination of lamps on the market emphasizes the importance of purchasing from the oldest and largest manufacturing company whose reliability as to uniform and accurate standards and ratings is established. 7 THE GENERAL ELECTRIC COMPANY'S INCANDESCENT LAMP FACTORY AT HARRISON, Capacity Per Day 60,000 Incandescent Lamps— Annual Production 15,000,000 Lamps. GENERAL ELECTRIC COMPANY While the low prices of the past three years have compelled many lamp manufacturers to economize by abridging processes and neglecting vital points, the (ieneral Iflectric Company has imj)roved its methods and machinerv, given lamps more detailed attention than ever, and is now producing a lamp far surpassing in cpiality any lamp formerly sold at double the price. The immense annual production of fifteen million lamps makes these results possible and also permits the adop- tion of new improvements and the establishment of a laboratory for e.xperimental work at the cost of only a small fraction of a cent per lamp with a large produc- tion, but at a prohibitory cost to the average lamp factory producing only a few hundred thousand lamps per year. Ifx'idently a lamp company able to conduct such work on the most e.xtensive scale can offer its customers uniformity of product and e.xcellence in quality other- wise unobtainable. Among the many new processes which have tended to improve the quality of Ifdison lamps, the new method of exhaustion is undoubtedly the most important. The features and advantages of chemical e.xhaustion are now well known and require no further comments. It may be said, however, that the process has recently been perfected and the results obtained with it are outside of the range of possibility with the old mechani- cal or mercury pumps. Attention is called to the illustrations of the new standard form of bulb recently adopted. The interior volume and surface of the bulb have been increased with- out adding to the maximum diameter, and the heating and tendency to blacken are thus reduced. The bulbs of all lamps are molded and are uniform in shape and size. 9 BALL-ROOM OF THE HOTEL WALDORF-ASTORIA, NEW YORK GENERAL ELECTRIC COMPANY Our processes of manufacture are manifold, careful, and exact iipe,', embodying all the improvements and every detail that our judgment and extensive ex]ierience show are necessary to make a finished lamp of the finest appearance and highest cpiality — considerations always foremost with us. I'he results are as they should he. the Mdison lamp stands today absolutely unequalled, the standard incandescent lamp of the world. W’e were the first manufacturers of lamps and have always produced more than the combined output of all the other factories in America. W'e have by constant, careful, intelligent, and thorough work, steadily increased the commercial possibilities of the incandescent lamp, building up the market for it and supplying for )^ears a clientage of the largest lamp consumers in the world with the most perfect incandescent lamp on the market. 'I'he lulison lamp of today is farther than ever in ad- vance of other makes, and it has opportunities to improve at a far more rapid pace than is possible for any other lamp. The Tdison lamp with its eminent superiority is, therefore, rapidly leaving all competitors. Our present annual production of over fifteen million lamps enables us more easily to produce a lamp which justifies the following statement made several years ago by the largest consumer of lamps in the world: “Comparative tests of ‘New Type Edison Lamps’ with those of other makes, both Iuiroj)ean and Ameri- can, demonstrate that in maintenance of candle-power, efificiency and average life, the ‘New Type Edison Lamp’ surpasses them all.” THE SELECTION OF LAMPS X purchasing lamps the average customer considers only two points — the first cost of the lamp and the time it will last. Two other points are, however, even more important and should not be neglected. One is the initial economy of the lamp, or the number of lamps which can be supplied per horse-power. Lamps are classified accordins; to voltacre, candle-power, initial economy, and tN'pe of cap or base. The term initial economy is used to denote the amount of power consumed by the lamp at starting e.xpressed in watts per candle, as for example, “3.5 watts economy” means that the lamp requires 3.5 watts for each candle- jiower of light gi\ en, or that a 16 candle-power lamp would require 56 watts. High economy lamps that require small power per candle are more susceptible to variations of pressure and have shorter lives than low economy lamps that consume relatively more power per candle. The Ldison lamp is furnished in three different initial economies: 3. 1 watts per candle, or twelve 16 candle-power lamps to the mechanical horse-power. 3.5 watts i^er candle, or ten 16 candle-power lamj^s to the mechanical horse-power. 4 watts i)er candle, or eight 16 candle-power lamps to the mechanical horse-power. In the Hotel S^ivoy New York 12 GENERAL ELECTRIC COMPANY THE LIFE OF A LAMP The other important point to be considered is the period of useful life, beyond which it is economical to install a new lamp even though the old one be still unbroken. Mere life is not the principal feature of a lamp nor the most desirable. The fact that one lamp outlasts another, no more indicates superiority than docs the length of a ])lot of ground determine its area. A lamp may be made to give any length of life desired and \'et consume so much current as to make it cost more to burn than a lamp gi\'ing half the life but consuming less power. A lamp may also have long life and yet give so low an average of candle-power as to make it a very undesirable and worthless lamp. The features of first importance in an incandescent lamp are, therefore, economy (energy consumed for light gi\'en ) and maintoiance of candle-pozucr. The point to be observed in purchasing lamps is therefore to select the lamp in which the average candle-jrower, energy consumed and length of life are combined to produce the best and most economical results, — that is, to irive the trreatest amount of litrht for least cost. It is a fact demonstrated by impartial tests of scientific institutions and by the practical experience of the largest electric light companies, that the New Type Edison Lamp e.xcels all others in the most efificient com- bination of these desirable qualities. It is therefore the most economical lamp to purchase although its first cost is not the lowest. The following facts determine the conditions to which each type of lamp is best adaiited. Lamps of an economy of 3.1 watts per candle will give satisfaction only where the regulation of voltage at 13 GENERAL ELECTRIC COMPANY the Station is the best, or, in other words, where the voltage at all times is practically constant. Such regula- tion can be secured only by constant and intelligent attention, and the use of reliable indicators or volt- meters. lUumination of the U. S. Government Building at the Omaha Exposition Lamps of an economy of 3.5 watts ]ier candle shoukl he used where the regulation is fair, that is, where the ma.ximum variation does not e.xceed 4%. Lamps of an economv of 4 watts per candle should he ordered in every case where the ])lant is supposed to he self-regulating, receixes little or no attention, and has no reliable pressure indicator or voltmeter in constant use. 14 GENERAL ELECTRIC COMPANY Where the reg'ulation of Noltage is first-class, it is, of course, possible to obtain almost unlimited average life from any make of incandescent lamp of low economy. I’sing lamps of such prolonged life is, however, a decided mistake and is uneconomical in every way, as is shown in the following section and in the Appendix. We in\ ite correspondence regarding the particular conditions under which plants are operated, and will be pleased to CORRESPONDENCE aeb ise as to what economy of lamp REGARDING will best suit the recpiirements. LAMPS Whatever economy of lamp is selected, no one thing will so greatly increase the efficiency of the plant as the effort to maintain constant voltage at the lamps. The economy mentioned above is, of course, initial econom\', and, like candle-power, is nothing more than a specification for lamps. It must not be confounded, as it often is, with the average economy given by a lamp during its life. The latter is determined by the candle- power maintenance and is a true measure of lam[) cpialit}', while initial economy is not. THE PROPER USE OF LAMPS LAMP to give satisfaction must not only be prop- erh' made, but it must also be prop- erl)- used. A lamp of the highest cpialit)- may be so misused as to give only a small frac- tion of its rated light capacity. I’roper use, pro- ducing a ma.xi- mum of light at a minimum e.vpense recpiires: That the lamps be burned at marked voltage; That the voltage^be kept constant; That lamps be replaced whenever they get dim. The last requirement is not considered economical by many users who prize lamps that have long life and insist on using them as long as they will burn. Let us see by an e.xample if extremely long life is desirable. As the cost of current varies greatly, we will assume an average cost of one-half cent per lamp hour. If a rated i6 candle-iiower lamj), burned for looo hours, be burned an additional icoo houns, it takes practically the same current during the last period, but gives an average light of only about 8 candles. The cost of i6 GENERAL ELECTRIC COMPANY current for the 2000 hours is $10.00. A new lamp costs 20 to 25 cents, and had three lamj^is, with a life of about 700 hours each, been used during the entire period, the average light would have been fully doubled, at an added e.xpense of not more than 50 cents or 5% of cost of current. In other words, by adding 5% to operating e.xpenses (representing the cost of the two renewal lamirs) the customer would add 100% to the light gi\ en. ( )ne new lam]) gives a light equal to two old ones at half the cost of current. If the old lamps gave light enough, the new lamps would halve the number of lamps in use and produce the same light with half the current. It is im])ortant to note that the above example is based on residts obtained with the highest grade of lamps. W ith an inferior quality of lamp the argument against extremely long life would be still stronger and the neces- sity of frequent renewals of lamps much greater. Thus, from an\' jroint of view, it is false economy to select lamps with a sole regard for long life. Lamps should be renewed when dim, for in no other way can light be jiroduced economicallv. The points to be remembered are as follows: Do not run pressure above the voItag:e of the lamps* Increased pressure means extra power, and although old lamps may thus give more light for a while, every new lamp that does not break from excessive pressure will deteriorate very rapidly and give greatly diminished light. Do not treat incandescent lamps like lamp chimneys and use them until they break. They should be renewed whenever they get dim. d he section on Life and Candle-jiower in the Ap- pendix of this ])ami)hlet gives a complete discussion of this subject A Column in the Dining Room of the Hotel Netherland, New York I GENERAL NOTE LAMP BASES All lamps (not miniature,' sup- plied by the General Electric Company arc fitted with Stand- ard Edison Screw Bases, or any of the following bases : Westing- house, Thomson-Houston, United States, Brush-Swan, Edi-Swan, Hawkeyc, Mather, Perkins, or Schaeffer. FROSTING jZ .jJt AND COLORING Any lamp can be furnished frosted, or in almost any color, either dipped or in natural glass. STANDARD 50 VOLT INCANDESCENT LAMPS general electric company 4, 6 , 8, AND 10 CANDLE-POWER 50 VOLT LAMPS F or service requiring only a moderate quantity of light, we furnish 4, 6, 8, and 10 candle-power lamps. Owing to the e.xtreme fineness of the filaments, these lamps are more sensitix e to variation in voltage than standard 16 candle-power lamps of the same economv. h'or this reason, to secure uniform average life, lanqis of low candle-power should be ordered of lower economv than the standard 16 candle-power lamps to operate under the same conditions. The filaments being comparatively short and stiff are best adapted to the looj) form. SPECIFICATIONS A Column in the Ifulb -Molded-Peai'-shaped. Size as P.trIor of the Hotel S.ivoy j,-, illustration. New York ]-'ilament — Loop in 45 to 60 volt lamps ; spiral in 60 to 90 volt lamps. \h)ltages~ 45 to 90. Econom\- — 4 candle-i)ower lanqis, 5 watts per candle; 6 candle-jxiwer lamps, 3.6 and 4.5 watts per candle; 8 and 10 candle-ixiwer lamps, 3.1, 3.6 and 4 watts ])er candle. The 10 candle-power 4 watt lanq) is furnished in the .same size bulb as the standard 16 candle-power 50 volt V 4, 6, 8 and 10 Candle-power 50 Volt Lamps general electric company i 6 , 20 , AND 24 CANDLE-POWER 50 VOLT LAMPS 0\\’ voltage lamps, b\ reason of their heavier fila- ■I— ' ments, give slightlv better results than can he obtained with high voltage lamps. This superioritv permits of the use of 3.1 watt lamps in place of lamps of 3.5 watts or lower economies. W'e ha\ e for some years supplied a large number of alternating current stations with 50 to 55 volt, 3.1 watt lamps. The service they give is e.xcellent. The use of such high economy lamps, besides saving power, keeps the ax erage life from being too prolonged. I'he life of low voltage 3.5 and 4 watt lamps outlasts their usefulness, and therefore the higher econoni}' 3.1 watt lamps are desirable. W’e use the looj) form of filament because it is the best permissible with a filament necessarilv too short and stiff for the spiral form. SPECIFICATIONS Bull) — Molded-Bear-shai)ed. Size as in illustration (e.\cej)t the 20 candle-power, 4 watts per candle, and the 24 candle-power, 3.6 and 4 watts per candle lamps which are in larger bulbs). Filament Loo]) in 45 to 60 volt lamps; spiral in 60 to 90 volt lamps. X’oltages — 45 to 90. Fconomy--i6, 20, and 24 candle-power lamps, 3.1, 3.5 and 4 watts per candle. 16, 20 and 24 CaniIc-powc»- 50 Volt Lamps GENERAL ELECTRIC COMPANY 32 CANDLE-POWER 50 VOLT LAMP W l'L have adopted the voltage lamps in ])refi we have tried and discarc filament, to give the best results in maintained candle-power and free- dom from blackening, requires a length too short to wind in a well formed spiral. The spiral filament, owing to the weight of the coil at the end, tends to droop more than the loop. Altogether our e.xtensive e.xperience with low voltage lamps shows that the looj) form of filament makes a better lamp. SPECIFICATIONS loop filament for our low erence to the spiral, which led. The proper size of If ul b — M ol ded - Pear-shaped. Size as in illustration. In the Ball-room of the Hotel h ilament — Loop in Waidorf- Astoria 45 to 6o volt lamps: si)iral in 6o to 90 volt lamps. X’oltages — 45 to 90. I'iconomv — 3.1. 3.6 and 4 watts per candle. 26 32 Candle-power 50 Volt Lamp GENERAL ELECTRIC COMPANY 50 CANDLE-POWER 50 VOLT LAMP A PK()lMCk ])r<)j)()rtion should always be presL'rvcd between the size of the bulb and the candle-power of an incandescent lamp. Too large a bulb is unneces- sarily heavy, occupies much space and is hulk\' in ajipearance, while too small a bulb causes undue beating and blackening. The illustration of our standard 50 can- dle-]5ower low voltage lamp clearl)' shows the harmony of ])roi:K)r- tion m candle-power and size of bulb. 'I'be lulison lamp, as is well known In' all users, also maintains a full ratio of light given to power consumed, to a greater degree than any other lam]L ( )ur 50 candle-power lamps accurate and perfect In a Corridor of the Hotel Waldorf-Astoria can be depended coiistruction. SPECIFICATIONS Hull) Molded-l’ear-sbaped. Size as in illustration. I'dlament Loop. X'oltages — 45 to 90. I’icononiN' — 3.1 and 3.6 watts per candle. 50 Candlc-pDwcr 50 Volt Lamp GENERAL ELECTRIC COMPANY 100 AND 150 CANDLE-POWER 50 VOLT LAMPS 11 ]C mechanical structure of the heavy filaments in A hi^h candle-power lamps requires special attention. W'e have found that the jj^reatest strength and rigidity are secured bv the use of the double loop as shown in the illustration on the folded page. These loops are connected in multiple and burn as two separate carbons. The chances of failure are thus reduced one-half, for should one filament break the other remains and the lamp will burn at half candle-power. As great dejiendence is placed on every high candle-power lamp, reliability is of marked importance. The value of our careful and c.xact processes is realized in this type of lam]). Si)ecial attention is called to the heavy currents carried by these high candle-power lamps and the conse- quent imixirtance of having a large and certain area of contact between base of lamp and socket. For these lamps 6 to 9 amj)eres at 50 volts are required, and on this account they should be ordered with bases to fit Keyless Socket for High Candle-power Lamj)s. (Cat. Xo. 8319). These sockets are sj)ecially designed to carry large currents, and smaller .standard sockets in general use are not reliable for this })urpose. These high candle- ])ower lam])s are ])referably used in keyless sockets, but in any case the current should be turned off and on at the switch and not at the socket. SPECIFICATIONS Hull) — Arolded-Pear-sha])ed. Size as in illustration, h'ilament Double loop, the two loo])s in multiple. \h)ltages- 45 to 90. Economy -100 candle-power lain]), 3.1 and 3.6 watts l)er candle; 150 candle-])ower lam]), 3.1 watts ])er candle. Hased with High Candle-])ower Hase to fit .Socket, Cat. X'o. 8319, or with any standard bases. 30 A Column m the Dining Room of the Hotel Majestic New York i I 100 lO 125 VOLT INCANDESCENT LAMPS GENERAL ELECTRIC COMPANY 4, 6, 8 AND 10 CANDLE-POWER 100 VOLT LAMPS T 1 1 ]-2 use of 8 and lO candle-power lamps has yreatly in- creased m recent years, especially amoiye; residences. ( )win“' to the extreme fineness ol their filaments, these lamps have not the stability and endurance of standard i6 candle-power lamjis, and their manufacture involves j^'reat difficulties. Helie\ii\L;', howex'cr, that such lamps will always be in large demand, we have, through con- centrated efforts, matle marked improxements, and are now able to offer an 8 or lO candle-iiower lamp approach- ing in quality our standard i6 candle-power lamp. h or general serx ice, where regulation is not perfect, nohighereconomy than 3.5 watts per candle should be used. Electric signs, hall and closet lighting, rec|uiring small lighting units, have producetl a demand for 4 and 6 candlc'-power lamj^s. To give such lamps equal sta- bility with lamps of higher candle-iiower, they are made to consume Irom 4 to 5 watts per candle. SPECIFICATIONS Bulb- Volded-Bear-.shaiied. Size as in illustrations, h'ilament— 4 candle-ptiwer lamp. Spiral, specially for sign work. I'ilament— 6, 8 and 10 candle-power lamps. Oval, A nchored. X'oltages— 90 to 123. Economy — 4 candle-iiower lamp, 5 watts per candle; 6 candle-power lamp, 3.6 and 4.3 watts per candle; 8 and I o candle-power lanqis, 3 c S-f* 4 watts iier candle. 4'he 10 candle-power 4 watt lamp has the same size bulb as the standard 16 candle-power lamp. 4 Candle-power JOO Volt Lamp 6, 8 and 10 Candle-power 100 Volt Lamp 33 GENERAL ELECTRIC COMPANY 16 CANDLE-POWER 100 VOLT LAMP T he 1 6 candle-power high voltage lamp is the stand- ard of comparison which distinguishes the high grade manufacturer from the incompetent. The difficulties met in making a perfect 50 \ olt lamp are multiplied when the 100 volt lamp is attempted. The increased voltage acting upon a finer filament results in rapid deterioration and loss of candle-power, unless its construction has been given careful attention bv e.xperienced workmen. The average manufacturer is, therefore, unable to produce a high loltage lamji of higher efficiency than 3.5 to 5 watts per candle. The successful production by us of a commercial 3. i watt, higb voltage lamp, has been largely instrumental in bringing incandescent lighting to its present advanced stage. The standard New Type fulison Lamp here illus- trated is today the most e.xtensivelv used lamp in the world and iqion it has been concentrated the greatest amount of skill, time and attention. All its numerous good points cannot be shown in an illustration. Clean white light, uniform and highly sus- tained brilliancy, and good average life, are among the most notable superior cjualities which can be appreciated onlv by using the lamp. The carbon filament is an- chored securely in position, ami thus prevented from vibrating or touching the glass. The filament is shaped to fit the bulb so as to form a bright sphere instead of two lines of light. SPECIFICATIONS bulb - Alolded-l’ear-shaped. .Size as in illustration, excepting the 20 c.p., 4 w.p.c., and the 24 c.p., 3.5 w.p.c. and 4 w.p.c. which are in larger bulbs. I'dlament ( )\ al, Anchored. \'oltages--90 to 125. Economv -16, 20 and 24 candle-power lamps, 3.1, 3.5 and 4 watts j’ler candle. 34 16 Candle-power 100 Volt Lamp GENERAL ELECTRIC COMPANY 32 CANDLE-POWER 100 VOLT LAMP T he beauty of form and brilliancy of the oval fila- ment are strikingly illustrated in our higher candle- power lamps. The oval filament produces a sphere of light e.xactly filling the bulb and its m a n y advantages enumerated in the description of the i6 candle-power lamp are here accentu- ate d. O u r n e w chemical e.xhaustion process is of special advantage in the pro- duction of 32 candle- power lamps. It overcomes man}' of the special difificul- ties in the e.xhaustion of high candle-power lamps — blackening is reduced, mainte- nance of candle- power is increased and the quality of the average lamp is materially improved. SPECIFICATIONS Bulb — Molded-Bear-shaped. Size as in illustration, excepting the 4 w.p.c. lamp which is in a larger bulb, b'ilament — Oval, Anchored. X’oltages — 90 to 125. ICconomy — 3.1. 3.6 and 4 watts per candle. Electrolier in Hotel Savoy, New York City 36 32 Candle-power 100 Volt Lamp 37 GENERAL ELECTRIC COMPANY 50 CANDLE-POWER 100 VOLT LAMP A n anchor is of special value in retaining in form and position the heavy filament required in a 50 candle-power lamp. The compact shape of the oval avoids the necessity of using a large and bulky bulb. Our new exhaustion process produces 50 candle- jiower lamps in which blackening is reduced, maintenance of candle-power increased and weak spots in filaments avoided. The construction of our 50 candle-power lamp is accurate and thorough — features that are especially desirable where reliance is jdaced on single lamps in service. SPECIFICATIONS Hulb —Molded -I’ear-shajK'd. Size as m illustration. h'ilament — Oval, Anchored. X’oltages — 90 to 125. Economy — 3.1 and 3.6 watts per candle. 3S 50 CandIc-pDwcr 100 Volt Lamp GENERAL ELECTRIC COMPANY 100 AND 150 CANDLE-POWER 100 VOLT LAMPS R eliability is a feature of prime importance in high candle-power lamixs. When dependence is placed on a single lamp, its failure from any cause is more serious than the failure of one of many lamps of lower candle-jiower. Our exact processes and indi\ idual treatment secure perfection in every lamp. The loo and 1 50 candle-power lamp is shown in the illustration on the folded page. Lor mechanical reasons we have found the double loop the most desirable form of filament for these lam|is. The two loops being arranged in series, each loop is only half the length neces.sary with one continuous filament, and has many times the strength and rigidity. These lamps should be ordered with base to fit Keyless Socket for High Candle-power Lamps. ( Cat. No. 8319.) This .socket is specially designed to carry large currents, and smaller standard sockets in general use are not reliable for this purpose. It is recommended that high candle- power lamps be used in keyless sockets, or in any case, that the current be turned off and on at the switch. SPECIFICATIONS Bulb — Molded- Pear-shaped. Size as in illustration, h'llament Double loop, the two loops in series. X’oltages — 90 to 125. Economy — 100 candle-jiower lamp, 3.1 and 3.6 watts jier candle; 150 candle power lamp, 3.1 watts per candle. DESIRABLE FORM OF FILAMENT ■to An Oxley & Enos Company Lighting Fixture GENERAL ELECTRIC COMPANY THE STREET RAILWAY LAMP A n unanchored rtlanient, to withstand the shock and vibration of street car serx'ice, has to be so short and stiff that the light is limited to a very small area. The efficiency and maintained brilliancy of the lamp is thus reduced, as well as the general illumination of the car. The position of the anchor is also an important consideration. Anchoring the lower end of the filament to the inside of the bulb is objectionable, as it holds the filament too rigidly and the effect of a shock or jar is to break either the filament or the anchor. E.xcessive rigidity cannot be overcome by resting the filament loosely in the anchor, since vibration of the filament against the anchor will cause it to wear away. With a metal anchor firmly connected to the stem or inside part of the lamp, as in the Edison oval filament, shown in the accompanying illustration, the ideal arrangement is secured. The filament is held so as to check vibration rather than to entirely prevent it. Ereedom of vibra- tion within proper limits is, therefore, allowed and the filament is not strained or weakened. With the anchor m the position shown, the whole filament vibrates together and there is practically no danger of the branches interlocking and short-circuiting, as would be the case if one branch of the spiral were anchored rigidly to the side of the lamp, and the other branch free to vibrate and strike it. Another necessary consideration in the case of Railway Lamps is that they should have uniform cur- rent capacity since they are ojK'rated in series. Our Railway Lamps are made in three different classes, viz.: for 500 volt circuits, for 550 volt circuits and for 600 volt GENERAL ELECTRIC COMPANY circuits. In each class, lamps are selected of a given amperage to within .01 ampere. Thus carefully tested for candle-power and current these lamps are suited e.xactly to the requirements of street railway service and give uniform light and life. Street Railway Lamps of 33 candle-power or other candle-powers are furnished to order. SPECIFICATIONS Bulb — Molded-Bear-shaped. Size as in illustration, h'ilament — Oval, Anchored. Ifconom}' — 4 watts ]ier candle. l‘'urnished for operating five in series on circuits of a total of 500 \'olts, 550 volts or 600 volts. 42 The Street Railway Lamp 43 SPECIAL INCANDESCENT LAMPS GENERAL ELECTRIC COMPANY 200 TO 250 VOLT LAMP E furnished lamps for 200 and 250 volt circuits on ” special order for several years before the general public knew that sucb a lamp was practicable. Their successful use has increased the annual sales of these lamps to more than 350,000. A perfect vacuum is of the greatest importance with these high voltage lamps, for unless all the residual gases are thoroughlv removed from the bulb the lamps are liable to e.xplode at the high voltage. If an e.xplosion, blowing the lamp into fragments and causing serious short-circuits,does not occur in a badly exhausted lamp, the inside connections may melt. Our new process of exhaustion is, therefore, of special value in the production of these lamps. By this method, individual exhaustion insures a perfect vacuum in every lamp and reduces the danger of e.xplosion or failure to a minimum. Owing to the increased strain to which the carbtms or filaments are subjected by the high voltage, these lamps are uncommercial except in the lower economies. The economy of our regular product is 4 watts per candle, and in its average life and maintenance of candle-power, is somewhat better than our standard 100 to 125 volt 3.1 watt lamp. The illustration shows our latest type of 200 to 250 volt lamp. The length of filament necessary in this type of lamp is most advantageously arranged in a double oval which is firmly held in position by t 7 vo anchors. Such an arrangement is much neater than the method of anchoring to the inside of the bulb, and it avoids shadows. An anchor from the lower end of the filament to the inside of the bulb is useless, as the 46 GENERAL ELECTRIC COMPANY anchor breaks off with a slight shock and the wcii;ht of it destroys the filament. The ICdison filament is so anchored as to alio w some \ibra- tionandthns relieve the strain on the filament, bnt the vibra- tions are checked so as not to ex- ceed proper limits. These lamps a r e made in 8, 10, 1 6, 20, 24, 32 and 50 candle- power. SPECIFICA- TIONS Bulb— M 0 1 d e d - Pear-shaped. Size as in il- lust rat ion. Filament — Donbleoval, Double an- chored. \’oltao-es — 200 to 250. ICcononn' — 4 watts per candle. GENERAL ELECTRIC COMPANY ROUND BULB LAMPS F or window or other decorations and for all installa- tions where a short bulb is desirable, we offer our Round Bidb Lamps. The bulbs are 2^" in diameter and make a very neat compact t) pe of lamp. The oval form of anchored filament pro\'ides the best arrangement for the long filament of high voltage lamps in small round bulbs. In low voltage lam]is the shorter and stiffer filament is well adapted to the spiral and loop forms. The round bulb lamps are frequently used in street railway service, in headlights and else- where. The)' can be obtained specially selected for amperes when desired for railway service. SPECIFICATIONS Bulb — l\Iolded-Spherical-2|-" in diameter. Filament, too volts and over — (')val. Anchored. Filament, 50 to 60 volts — Spiral. \h)ltagcs — 45 to 125. Flconomy, 8, 10 and 16 candle-power lamps — 3.5 and 4 watts per candle. Lamps of 4 and 6 candle-power in this tyjie can be furnished if desired, also 32 and 50 candle-power in larger bulbs. 48 Round Bulb 1 00 Volt Lamp Round Bulb 50 to 60 Volt Lamp 49 GENERAL ELECTRIC COMPANY TUBULAR LAMPS T LU^ULAR or “Bunghole” Lamps are useful in con- fined or narrow places. The}’ were originall}’ made for examin- ing the interior of casks and barrels, the lamps being inserted through the bunghole. These lamps are also frequently used on candelabra and resemble lighted candles. They are also effective for show case illumina- tion as they can be concealed inside the case underneath the moulding strips. With the tub- ular form of bulb, the loop fila- ment anchored at the lower end to j^revent sagging, is most suitable. SPECIFICATIONS Bulb — Molded. The illustration shows the lOO volt lamp full size. The 50 volt lamp is one-half inch shorter than the 100 volt lamp. Filament — Loop, Anchored. \’oltages — 45 to 125. Fconomy, 8 and 10 candle-power lamps — 4 watts per candle. Fconomy, 16 candle-power lamps — 3.1 watts per candle. Lamps of 32 c.p. in this type can be furnished if desired, but will be made with larger bulbs. 50 Tubular Lamp 51 GENERAL ELECTRIC COMPANY STEREOPTICON LAMPS T O meet a large and constantly increasing demand, we supply a specially designed lamp for stereopti- cons. A comiDact filament is here essential so that the light shall be radiated as nearly as possible from one point. As these lamps are required only in the higher candle-powers, the filament is necessaril}' heavy and must not be too closely bent. The conical spiral fila- ment of our lamp meets these conditions most satis- factorily. The illustration shows the 50 candle-power stereop- ticon lamp full size. W’e also manufacture lower and higher candle-powers to special order. SPECIFICATIONS Bulb — Molded-Round. h'ilament — Conical spiral. Voltages — 45 to 125. Economy — 4 watts per candle. 52 53 Stercopticon Lamp GENERAL ELECTRIC COMPANY THE EDISON NIGHT LAMP N objection to the incandescent light has always TTl been that it could not be turned down or dimmed. This objection has been overcome in the Edison Night Lamp. A simple movement of the milled screw provided on this lamp changes the candle-power from si.xteen to one. The device is economical as well as simple since the current consumed is reduced with the candle-power. This lamp can be furnished without the screw, if a permanent low candle-power lamp is desired. The bulbs are always frosted. The Night Lamp is particular!}' adapted for use in hospitals, nurseries, bed-chambers, halls and closets. SPECIFICATIONS Bulb — Molded-Pear-shaped. Size as in illustration. Filament — Oval, Anchored. Voltages — 45 to 125. 54 55 The Edison Night Lamp GENERAL ELECTRIC COMPANY RESISTANCE LAMP B anks of lamps for resistance are in quite general use and are ver\' satisfactor\' for moderate currents. We ha\-e f(jr years had a large demand for specially made resistance lamps, of the type shown in the illus- tration. Resistance lamps are furnished in tubular bulbs, in order that the\- can be packed closel}' and thus minimize space. The filaments are loops connected in series to give the required resistance. Lamps of this type can be furnished of any desired resistance up to looo ohms cold, and for currents up to fi\’e amperes, the power consumed per lamp not to e.vceed loo watts. Resistance lamps of higher power consumption can be made in larger bulbs on special order. In ordering state resistance and the current in amperes at which this resistance is desired. SPECIFICATIONS Bulb — AIolded-Tubular. Size as in illustration, h'ilament — Loop. Resistance — As stated above. 56 Resistance Lamp For Miniature Lamps and Appliances and any Special Lamps not Described in this Catalogue, Address Edison Decorative and Miniature Lamp Dept,. General Electric Company, Harrison, N. J. GENERAL ELECTRIC COMPANY CANDELABRA AND DECORATIVE LAMPS 1 1 1 C practical ajiplication of C a n d e 1 a b r a Lamps in dec- orative interior lighting' has be- come so general and so well un- derstood that any special re- marks in the sense of ex- ploitation are nnnecessary. The Scries Candelabra Lamps which were intro- duced by ns a few )'ears ago have constant- Iv grown in public favor, and are now in extensive use, chiefl\' for decorative lighting in residences, hotels and other places for which they are eminently suitable. The favorable reception that this form of lighting has met, has led to a demand for lamps of the same general stvles and sizes capable of being used in multiple, instead of in series, on circuits of from lOO to 120 volts. Anticipating such a demand, we produced several st\'les of multiple burning Camlelabra Lamps, which arc shown in the following pages. W’e have found them to be a product that has met with instant favor and, in con- 61 In the Parlor of the Hotel Majestic GENERAL ELECTRIC COMPANY sequence of their many points of excellence, the demand for them has rapidl)’ grown. d'he Special Series Lamps have also retained their great popularity for all kinds of tem])orary and permanent deco- rati\e and elec- tric sign work. In this branch we have also added a multiple burning lamp to meet a demand for such a t\ j)e of lamp, to be used more es- pecially in electric sign work. This lamp has filled many require- ments for that special use that could not be met by the series lamps. All of these lamps, however, series and multiple, have their jiroper sphere of utility, according to the circumstances under which they are to be used. It is proper to call special attention also to our Sockets and Receptacles. Many improvements have been made in them, not only with regard to their useful- ness and to the coin enience of handling, but with a view to their ajqiearance and increased safety from a fire underwriter s standpoint. It will be found from a careful e.xamination of the sockets and receptacles listed in the fol- lowing pages, that we have so devised them as to provide for all contingencies that could be reasonably anticipated. 62 GENERAL ELECTRIC COMPANY REGARDING SERIES LAMPS T 1 1 1 C lamps shown on jia^es 64, 68 and 69 are made esjieciallv for series burning on electric light- ing circuits. Particular attention is called to the following general remarks on these lam])s. If these reinarks are care- fully read before ordering or using an\' of these series lam]Ls, purchasers will save themselves and us considerable trouble, ex- pense and delay. The most important point in burning lamps in series is that the amperes of each of the lamps in any one series should be the same within three one- hundredths of an amjrere. The voltage of the lamps may var\-, but the sum of the voltages in any series must ecpial the voltage of the cir- cuits within three volts. In selecting lamps for am- one series, use only lamps of aiiproximately the same amperes and see that the sum of their voltages equals the voltage of the circuit. In replacing a lamp which has burnetl out m any scries, use only a lamp of the same voltage and amperes as the one broken. In ordering series lamps to replace those burned out, give both voltage and amperes of those in use, also voltage of circuit. <>3 SERIES CANDELABRA LAMPS GENERAL ELECTRIC COMPANY SERIES CANDELABRA LAMPS S l-HvIES candelabra lamps are made in five different styles, A, B, C, D and E, and are furnished, when specified, to be used two, three or four in series on electric lighting circuits of lOO to 120 volts, and two in series or in multiple on circuits of 50 to 60 volts. Style A is always a 10 candle-power lamp. Styles B, C, D and E differ from each other only in the shape of the bulbs, but they all ^ , differ from the style A lamp in that the candle-power of the lamp varies according to the number used in series. On 100 to 120 volt circuits, two lamps in series give 8 candle- power each — three in series, 5 candle- power each — four in series, 4 candle-power each. If burned in multiple on circuits of 50 to 60 volts each lamp will give about 8 candle- power. All colored candelabra lamps are made of natural glass, e.xcept amber-colored, which are dipi^ed. Lbrless otherwise ordered the Style D frosted, as a better effect is thereby obtained, made in colors. A 7 )iperes and volts are etched on each lanip. Note directions for ordering, page 63. The above lamps will fit Candelabra lamp is It is not and Receptacles Nos. i, 2, 3, and 74. Sockets 6 and 7, pages 72, 73 65 GENERAL ELECTRIC COMPANY MULTIPLE CANDELABRA AND SIGN LAMPS M LU/riPLl'^ canclekibra lamps, St)'les A, 15 , D and E ha\'e been especially designed for burning in multiple on circuits of lOO to 120 volts. In ordering these lamps the voltage of the eircuit should be specified and the lamps be designated as Multiple Candelabra Lamps, Styles A, B, U or E to dis- tinguish them from the Series Cande- labra Lamps of the same styles. The multiple sign lamp. Style F, was especially designed to fill a de- mand for small lamps to burn in multiple in illuminated signs ha\ing letters from ten inches to two feet in height. It has attained a great popu- larity for use in this connection, as well as in many other lines on account of its size, beauty, candle-power, and economy in the use of current. It is an 8 candle-power lamp, is furnished for use in multiple on circuits of 100 to 120 volts, and takes a current of about .28 ampere. In ordering these lamps, the voltage of the circuit should be specified. All colored multiple candelabra and sign lamps are made of natural glass, except amber-colored, which are dipped. Lbiless otherwise ordered the Style 1 ) lamp is frosted, as a better effect is thereby obtained. It is not made in colors. Note directions for ordering, page 63. The above lamps will fit Candelabra Sockets and Receptacles Nos. i, 2, 3, 6 and 7, pages 72, 73 and 74. 67 GENERAL ELECTRIC COMPANY SPECIAL SERIES LAMPS 8 Candle-power 2 in series on 100- J20 volts. In multi- ple on 50-60 volts. Current required for each series will aver- age about .50 amp. 5 Candle-power 4 in scries on JOO- 120 volts. 2 in scries on 50-60 volts. Current required for each series will aver- age about .55 amp. T he following lamps are called “Special Series” Lamps to distinguish them from Candelabra and Batter)- Lamps. We furnish these in four different candle- powers for burning m series on electric lighting circuits of too to 120 volts, or on circuits of 50 to 60 volts. 6S GENERAL ELECTRIC COMPANY The 8 candle-power lamp is used for decorative pur- poses where large units of light, but few in number, are desired. In illuminations coveringf a large area this lamp can be used advantageous- ly. It is also used in multi- ple for illumi- nated signs on 3 Candle-power 8 in scries on I OO-1 20 volts. 4 in scries on 50-60 volts. Current required for each scries will average about I amp. I Candle-power 8 in scries on I00-I20 volts. 4 in scries on 50-60 volts. Current required for each scries will average about .33 amp. Special Scries Theatrical Lamp 50 to 60 volt circuits. The 5 candle-power lamp is also used for decorative purposes where large units of light, but few in number, are desired, and it can be used advan- tageously in illuminations covering a large area. It is used quite extensively in decorative sign work where the effect to be obtained is not based upon the employment of large units of lights but upon the special design or the number of lamps used. The 3 candle-power lamp is used for decorati\ e pur- poses in cases where plenty of current is obtainable. Wc do not recommend its use where lamps are to be placed 69 GENERAL ELECTRIC COMPANY close together, as in sign work and many cases of floral decorations, because it becomes quite hot in continual use. The I candle-power lamp is that which we most strongl)' recommend for sign and decorative work where lamps are to be placed close together. It gives a good light, generates very little heat, and each series requires only about one-third of an ampere of current. It is therefore, the best small lamp for series work, whether for interior signs, 'among flowers, or otherwise. The theatrical lamp is made to give i candle-power, burning i6 in series on lOO to 120 volt circuits or 8 in series on 50 to 60 volt circuits. It is e.xtensively used for theatrical purposes, for decorating dancers and produc- ing special effects. Each series takes about one-half ampere of current. This lamp is carried in stock as an unbased (or wire) lamp, and will be so shipped unless otherwise ordered. If desired it will be furnished fitted with miniature screw base to fit No. 4 Receptacle or No. 5 Socket. All colored series lamps are made of natural glass, except amber-colored, which are dipped. A 7 npcres and volts are etched on the S candle-power and 5 candle-power lamps. Note directions for ordering, page 63. The 8 candle-power and the 5 candle-power lamps will fit Candelabra Sockets and Receptacles Nos. i, 2, 3, 6 and 7, pages 72, 73 and 74. The 3 candle-power and the i candle-power lamps will fit Miniature Lamp Receptacle and Socket Nos. 4 and 5, page 72. 70 Candelabra in the Hotel Savoy New York GENERAL ELECTRIC COMPANY No. 2 Receptacle No. 4 Receptacle No. 6 Receptacle No. 3 Socket No. 5 Socket 72 GENERAL ELECTRIC COMPANY RECEPTACLES AND SOCKETS FOR MINIATURE LAMPS No. I is known as the Standard Round Candelabra Receptacle. It is made of porcelain and is especially despyned for use on h.xtures fitted with i;iass candles, d'he receptacle screws into a central supporting tube, anil the candles, when in place, completely cover both supporting tube and receptacle. It will re- ceive lamps having candelabra screw base. No. 2 is the Standard h'lat Base Candelabra Recejitacle. It is made of porcelain and will receive lamps shown on pages 64, 66 and 68. No. 3 is the Candelabra Socket. It is made of brass, with porcelain insulating parts, and will recei^■e lamps shown on pages 64, 66 and 68. No. 4 is the Standard Round Miniature Lamp Receptacle. It is made of porcelain and will receive the 3 and I candle-power lamps fitted with miniature screw base — page 69. No. 5 is the Standard Socket for use with Miniature Lamps. It is made of brass with porcelain insulating parts, and will receive the 3 and i candle-power lamps fitted with miniature screw base — page 69. No. 6 is a Special Receptacle for sign work, and is supplied with litharge lining for use in outdoor work if specially ordered. The No. 6 has been designed for strength and compactness and is very extensively used for No, I Receptacle 73 GENERAL ELECTRIC COMPANY sign work of all kinds. It is made of porcelain and will receive lamps shown on pages 64, 66 and 68. No. 7 is a Donble-pole Fused Receptacle which has been designed to meet the recpiirements of certain climatic conditions demanding the use of fuses in con- nection with the receptacle itself. It is also particularly suitable for many classes of inside work necessitating the use of an ornamental receptacle. This receptacle is made of porcelain and has a remo\’able cap or cover concealing both connections and fuses, yet permitting ready access thereto. It will recei\'e lamps shown on pages 64, 66, and 68. No. 7 Receptacle GENERAL ELECTRIC COMPANY SHADES FOR MINIATURE LAMPS A The star shade here illustrated is made especially for certain classes of decorati\ e woik, and presents a very handsome and striking effect when the lamps are lighted. The type of Shade-holder Attachment shown below is furnished for use with Sockets Nos. 3 and 5. It is made of brass and may be readily attached. As these attachments are not interchangeable for Sockets Nos. 3 and 5, customers should be careful in ordering to state with which socket the attachment is intended to be used. GENERAL ELECTRIC COMPANY The shades for miniature lamps illustrated below are intended for use with lamps shown on pages 69 and 78. Special shades for larger miniature lamps can be supplied on order. They are furnished in the following colors: Red, White, Blue and Green with edgings of different colors. 76 GENERAL ELECTRIC COMPANY BATTERY LAMPS The lamjis shown on the following j^ages are made especially for use with batteries and are not adapted They are made of 8, 10, i6, 20 and 24 candle-power, and from 8 to 45 volts, with an economy of from 2.5 to 4 watts per candle. for series work. They should not under any cir- cumstances be used for series lighting. Battery lamps as shown in the accompanying illustration are e.xtensively used for railway -car- riage lighting andforotherpur- poses in connec- tion with storage battery plants. They are made up in standard bulbs of about the size shown in the cut, and can be furnished to fit all stand- ard sockets. GENERAL ELECTRIC COMPANY BATTERY LAMPS-* Continued) The batter}' lamps here illustrated are described in the accompanying table. Wc' make no lamps taking less than J volts. DESCRIPTION. CANDLE- POWER. ELECTRO- MOTIVE FORCE. VOLTS. CURRENT REQUIRED. APPROX. AM PERES. Standard Battery Lamp 1 T i 8 to 0 4 to () 1.00 to .00 1.40 to .00 2 4 to 7 2.00 to 1.10 8 5 to 7 2..j0 to 1.75 • 4 7 to !l 2..50 to 1.75 () !) to 12 2.75 to 2.00 GENERAL ELECTRIC COMPANY BATTERY LAMPS • Continued) The battery lamps here illustrated are described in the aceompan}'ing table. 11 £■ niakc no lanips taking less than J volts. Dental Special Dental Special Dental Surgical Side Seal Side Seal Bottom Seal Lamp DESCRIPTION. CANDLE- POWER. ELECTRO- MOTIVE FORCE. VOLTS. CURRENT RE<)U1 RED. A PPKOX. A M P E R ES. Dental Lamp, Side Seal 1 H to 5 l.u to .(1 Special Dental, Side .Seal 1 T 75 to 5 1 .(1 to .(i Special Dental, llottom Seal .1 .'5 to 0 1.0 to .0 Surgical Lamp T 75 to 0 1.0 to .0 Pea Lamp T 7f to 5 1.0 to .0 i C.P. special The telephone lamps here shown are specially made for use on tele- phone switchboards. They are desig'iied to take a very small quantity of current. The volts and current required are as follows; One-fourth c.p., lo or 12 volts, .14 ampere. One-half c.p., 20 or 24 volts, .14 ampere. These lamps are fitted with a “spring jack” base for switchboard i c.p. service. 79 GENERAL ELECTRIC COMPANY BATTERY LAMPS- < Continued) The bicycle lavip here shown is the form and type of lamp most generally used with storage or primary battery for bicycle headlights, etc. It is of high economy, gi\ ing about J of ^ candle-power at 4 volts and .50 ampere. We also supply a sim- ilar lamp of about J Candic Fiat Lamp Bicydc Lamp candlo-powcr at 4 volts and .25 ampere. These lam])s are always furnished with miniature screw base to fit our No. 4 Recep- tacle or No. 5 Socket, unless otherwise ordered. The Diificr's lamp is a flat lamp of one candle-power arranged with loops at the top and bottom, l Candle Miner's Lamp in order that it can be hooked upon springs in the miner’s lantern and so held steady. This lamp re- quires about 3.5 to 5.5 volts, and .90 to 1 .40 amperes. The electromotive force re- quired for the flat lamps is 3 to 5 volts for the f candle-power and 7 to 9.5 volts for the 4 candle-power. The current required is .80 to 1.35, and 1.25 to 2 amperes, respectively. 4 Candic Flat Lamp 80 GENERAL ELECTRIC COMPANY BATTERY LAMPS (Continued) The electromotixe force required for the sphetical lamp is 7 to 9.5 volts. 'I'he current required is 1.25 to 2 amperes. The kineto- scope lamp is that originally adopt- ed for use in the lulison Kineto- scope, and it is still used there- with all over the world. As will 4 Candk Spherical Lamp. Pj. fj-Qj.,., ^he illustration, the filament is in spiral form, thus providing for concentration of the light in one spot. This lamj) is always furnished with miniature iAinctoscopc Lamp screw base, to fit No. 4 Recejxtacle or 4 Candic-power No. 5 Socket, unless otherwise ordered. ® Both of the microscope lamps here shown ha\e been designed to meet a growing demand for a small l^attery lamp easily fitted in various surgical instruments and holders. They both gix'e '/z candle-power from 3 to 5 volts, with an amperage of from .6 to i. GENERAL ELECTRIC COMPANY BATTERY LAMPS — (Continued) # , The 6 candle-power lamp shown here K has been especially designed for use with Automobiles. It is made for 6 candle-power at 22 and at 14 volts. It can be supplied based with either candelabra base (as in cut) to fit Nos. I, 2, 3, 6 or 7 Receptacles, or with miniature base to fit No. 4 or No. 5 Receptacles. A special wire lamp guard is supplied for this lamp, where there is danger of breakage. This guard is designed for connection to No. 3 or No. 5 Receptacles, and both guard and receptacle are nickel plated, presenting a hand- some appearance. The electromotive force required is from 30 to 38 volts, and the current from 1.75 to 2.50 amperes. Automobile Lamp Stick-pin Lamp Watch-charm Lamp We have not heretofore listed the stick-pin and ivatch-chann lamps, ha\’mg usuall)' sujoi^lied them only on special order. The demand for these ornaments has GENERAL ELECTRIC COMPANY them in stock BATTERY LAMPS ( Concluded) of late become so general that we have decided to cariA' regularl)'. The lamps are similar in appearance to an ordinar\' incan- descent lamp, but they are only dummies and cannot be lighted. \ The examination lamp for storage batteries shown m the accompanying illustration has been designed and is being suc- cessfully used for making e.xami- nations of the plates of large ac- cumulators. The bulb of the lamp is fiat and its diameter is as shown in the illustration. At- tached to the bulb is a glass stem about 40 inches long, making the total length of the lamp appro.ximately 42 inches. The two leading wires are insulated from each other and extend through the glass stem. Ordinarily the leading wires are attached to a flexible cord, which is connected with five of the accumulator cells. If de- sired, these lamps will be fur- nished with our candelabra screw base, or with regular standard bases, so that they may be con- veniently connected by means of our No. 3 Socket with flexible cord. These lamps are made to give 4 candle- power each at 10 volts, or 6 candle-power at 20 volts. OF INFORMATION ON INCANDESCENT ,) LAMPS GENERAL ELECTRIC COMPANY LIFE AND CANDLE-POWER OF LAMPS IXCE the prime function of a lamp is to give light, the best lamp is one that gu’es maximum light at minimum cost. Simple as this axiom is, few users of lamps fol- low it out in practice. Lamps are repeatedly selected for long life irrespective of good, uniform candle-power. Lamps are con- tinued in use long after their candle- power has seriously diminished. An e.xamination of the charac teristics of an incandescent lamp will give a clear understanding of the principles apphdng to their selection and use. A theoretically perfect lamp would maintain its normal candle-power indefinitely, or until the lamp was broken. In practice the deterioration of the lamp filament causes a steady loss of candle-power. The drop in candle-power is a characteristic of an incandescent lamp always to be borne in mind. The relati\'e drop or loss of candle-power, other things being equal, determines the comparative value of different lamps. We ma)’ have a lamp that loses 50% in candle- power inside of 200 hours on a 3. i watt economy basis. This type is almost invariabl)' furnished by the inexperi- enced manufacturer, and there are many such lamps in the market. Considered from the standpoint of life only, such lamps maybe excellent, because tbeir filaments deteri- orate to such a degree that it is practically impossible to supply enough current to brighten them up to the 86 GENERAL ELECTRIC COMPANY RENEWAL OF LAMPS breaking' point, but no discerning station manager would want such dim lamps even with unlimited life. .\s in the selection of incandescent lamps so in their use — the exclusive consideration of life leads to poor results. Loss of candle-power in a lamj) sooner or later makes it uneco- nomical to continue in use. There is no lamp {less than p suatts pereandle)yet made tvhich is eeonomieal to burn over 1000 hours, and in the great majority of eases the limit is under 6oo hours. An incandescent lamp is nothing more than a trans- former, receiving current and transforming it into light. After a certain time this trans- former may lose 50 % in effi- ciency, taking practically the same current, but giving only about one-half the light. A boiler or an engine suffering such loss in efficiency would be promptly repaired or replaced. The renewal of incandescent lamps is even more important. The old lamps jeopardize the customer’s trade with their poor and expensive light. A customer cares little how efficiently a station is operated, but is much concerned about the C|ualit\' of light furnished. At the present price of lamps, doubling the number of lamp renewals adds little to cost of operation, while it increases the lighting efficiency 40% to 50%. These principles are carefully obser\'ed by many of the large lighting companies, and a force of men or boys is employed to weed out and replace all dim lamps. Some such means of keeping the average life below 600 hours should be adopted by every lighting comiiany that has any regard for the economical jiroduction of light or the satisfaction of their customers. A simple method is to fix the average life at 600 hours or less and then determine from the station record ILLUMINATION OF OMAHA EXPOSITION GROUNDS-FINE ARTS BUILDING GENERAL ELECTRIC COMPANY how many lamps should be renewed each month to keep the averai;'e life within this limit. The required number of lamps should be renewed each month. If, for e.xample, a station decides on an axerage life not to exceed 600 hours and the station records show that on the average 60,000 lamp hours of current are sujrplied monthlx’, then it would be necessary to renew 100 lamjis a month. Some stations attempt to correct the dimness of old lamps by raising the voltage, but this is bad practice, since the increased jiressure damages every new lamp placed in circuit. THE IMPORTANCE OF GOOD REGULATION PROPER SELECTION AND USE OF TRANSFORMERS Poor regulation of voltage probably results in more trouble with customers than any other fault in electric lighting service. Some central station managers act on the theory that so long as the life of the lamp is .satisfactory, an increase of voltage, either temporary or permanent, will increase the average light. The fact is that when lamps are burned abox’e their normal rating the average candle- power of all the lamps on the circuit is decreased after several hundred hours of service, and if the station is on a meter basis, it increases the amount of the customers’ bills. Pixcessive voltage is thus a double error — it decreases the total light of the lamps, and increases the power consumed. The loss of light displeases the customers and discredits the service. If light is sold by meter, the increased power consumption dissatisfies the customers; if light is sold by contract, the additional power is a dead 89 GENERAL ELECTRIC COMPANY loss to the station. If increased light is needed, 20 candle-power lamps should be installed instead of raising the pressure. Their first cost is the same as 16 candle- power lamps; they take but little more current than 16 candle-power lamps operated at high voltage and give greater a\erage.lighL- - _ Increased pressure also decreases the commercial life of the lamp, and this decrease is at a far more rapid rate than the increase of ju'cssure as shown in the follow- ing table. This table shows the decrease in life of standard 3.1 and 3.5 watt lamps due to increase of normal voltage. EFFECTS OF CHANGE IN VOLTAGE STANDARD 3.1 WATT LAMP VOLTAGE I*ER CENT. 01 NORMAL. CANDLE- POWER PER CHN 1. OF NORMAL. WATTS PER CAN DLK- POWER. LIFE PER CENT. OF NORMAL. DETERIORA- TION PER CENT. OF NORM ^ I.. V m _ . — ■ 54 4 {\'A 1141 _j — - 11 111 5S 4.41 710 14 ‘l-i 02 4.21 7)00 IS !i;i 00 4.04 4:45 2:4 ii-i — 70..) 8.S1I :44.) 211 ;i:) “ — 7 •') ^ ;!.74 -77) oT) !l(i so o. ’)!» 220 45 !IT s.") :!.40 1711 50 !IS 00 140 Oil !lll ^ 10(1- — 101 ilo 1 ( M ) ;!.2i ;!.io ;!.oo 121 100 S2 S4 loo 100 122 10-i 1 12 2.111 OS 147 lo;: IIS 2.S2 7)() 1711 lof 124 2.7:4 40 217 10.') LIO 2.04 ;4s 20;4 loii LIT 1 — 32 :4i:4 90 GENERAL ELECTRIC COMPANY EFFECTS OF CHANGE IN VOLTAGE STANDARD 3.5 WATT LAMP VOLT.XGE PKR CENT, or NORMAL. V r CANDLE- pqWER PER CENT. OE NORMAL. WATTS PER CAN DLE- POWER. LIFE PER CENT. OK NORMAL. OETERIORA- \ riON e’erVent, of NO^AL. y ^ a.) y,-.,. a.3() 1*1 a() a. 99 hd 91 4.S.') lt;5 9 a 4.93 1»4 99 4.44 394 23 ha 73 4.29 319 H 32 t»(; 78 4.99 247 44 97 S3 3.93 193 31 98 SS — 3 . 7 s 1 33 Of) 99 100 94 1 00 3.64 129 loo 79 19(1 191 199 3.3 s S4 llS 192 111 3.27 (is 14(i 193 1 19 3.19 3S 173 194 123 3.0a 47 211 I9.i 129 2.9a 39 233 199 137 2.8.3 31 319 197 143 2.79 29 3S9 198 la2 2.9S 21 474 199 la9 2.99 17 373 119 197 2.33 19 OH 7 • * These tables show that a 3% increase of voltage on the lamp nearly halves the life, while 6% increase reduces the life by two-thirds. Irregular pressure, therefore, necessarily results in the use of lamps in which the power cc isumption per candle is greater than a well regulated pressure would allow. The result is reduced capacity of station, and reduced station efficiencv. GENERAL ELECTRIC COMPANY transtormer. THE SAVING RESULTING FROM GOOD REGULATION These remarks apply with special force to alternat- ing current stations, since we have here two sources of possible irregularity in voltage — the generator and the Poor regulation is most apt to occur in the transformers, and the utmost care should therefore be taken in their selection and use. The economy of the average lamp on alternating systems is nearly 4 watts per candle. With good regulation obtained by the intelligent use of modern transformers, the use of lamps of an economy of 3.1 watts per candle becomes practicable. It is thus possible to .save 25% in power consumption at the lamps and increase the capacity of the station and transformers by the same amount. In the past two years there has been a marked advance in the method of making transformer installa- tions. The general adoption of higher voltage second- aries gives smaller loss in wires and permits the use of larger transformer units, thus greatly improving the regulation. On this account 50 volt lamps are gradually going out of use. The replacement of a number of small transformers by one large unit, and of old, inefficient transformers by modern types, has also been of immense advantage to MODERN TRANS- FORMER PRACTICE stations. A large number of stations, however, still retain these old transformers, and load their circuits with large numbers of small units. Such stations necessarily suffer from loss of power, bad regulation, and a generally deteri- orated lighting service. Simply as a return on the invest- ment, it would !«}• all such stations to scrap their old trans- formers and replace them with large and modern units. 92 GENERAL ELECTRIC COMPANY Proper care in the selection of transformers con- siders the cpiality and the size. (Juality is the essential consideration and shonld have jrreference to hrst cost. .\o make of transformer should be permitted on a station's circuit that does not maintain its voltag'e well within 3% from full load to no loath d'he simple rule re.yardiny size is to use as large Imits as possible and thus reduce the number of units as far as the distribu- tion of service permits, h'very alternating station should aim to so improve regulation as to permit the satisfactory use of 3.1 watt lamps. Good regulation is eminently imjiortant to preserve the average life and light of the lamps, to prevent the increase of power consumed by the lamirs, and to per- mit the use of lamps of lower power con- sumption, so that both the efficiency and capacity of the station may be increased. Constant voltage at the lamjis can be maintained onlv by constant use of reliable, portable instruments. No switchboard in- strument should be relied on, without frequent checking by some reliable standard. Owing to the varying drop at different loads, constant voltage at the station is not what is wanted. Pressure readings should be taken at customers' lamps at numerous points, the readings being made at times of ma.ximum, average and minimum load. Not less than five to ten readings should be matle at each point visited, the voltmeter being left in circuit for four or five minutes and readings taken HOW TO MAINTAIN CONSTANT PRESSURE every fifteen seconds. The average of all the readings gives the average voltage of the circuits. Lamjrs should be ordered for this voltage, or if desired, the voltage of the circuits can be reduced or increased to suit the lamps 93 INCANDESCENT STREET ILLUMINATION-CHICAGO GENERAL ELECTRIC COMPANY in use. 'I'he practical points are to determine the a\-er- age volta^Lje at frequent periotl.s with a portable voltmeter at various points of the circuits, ami then to arran^m the voltag-e of the lamps ami circuits so that the\' agree. THE MEASURE OF A LAMP’S VALUE () determine relative values of various lamps, a correct basis cjf comparison must be established. Comparison should not be made solely according to how long lamps will burn, since the candle- power may seriously diminish. 1 he true basis of compari- son, considering both life and candle-power, is the average life of the lamps measured to a speci- fied limit of candle-power and called the useful life of the lamjx According to this basis of comparison, the best lamp, other conditions being equal, is the one which gives the longest useful life. Many central stations today consider that a lamp has passed its useful life when it has lost 20% in candle- power, i. c., when it has dropped to 80% of its initial candle-power. Using this Soyo limit, we have a definite basis for the determination of value and the correct comparison of lamps. It must not be forgotten that for this method of comparison equal conditions are essential. GENERAL ELECTRIC COMPANY The practical method of comparison is as follows: — Lamps of similar candle-power and voltage are burned at the same initial economy (3.1 or 3.5 watts per candle) on circuits whose voltage is maintained exactly normal. At periods of 50, 75 or 100 hours the lamps are removed from the circuits and candle-power readings taken, the lamps being replaced in circuit at the end of each read- ing. Readings are thus continued until the candle- power drops to 80% of normal. The results obtained are then plotted in curves, and the periods of time at which the average curve of each make of lamp crosses this 80% limit of candle-power give the relative \-alues. INCANDESCENT LAMP RENEWALS The necessity for frequent lamp renewals is urgent on all systems regardless of the cost of power and whether lamp renewals are charged for or furnished free. No matter how well constructed or ojierated an electric lighting plant may be, it cannot furnisb clear, good light unless the circuits be periodically swept clean of the dim lamps. This cleaning out of dim laiujis cannot be left to the customer. To be thorough and effective, lamp renewals must be made by tbe lighting company and without charge. Only by free renewals can a station have that complete control of its lighting service which is requisite 96 GENERAL ELECTRIC COMPANY to perfect results. 'I'he present price of lamps is so low as to make it possible for all stations to furnish free renewals at but slirtht e.xpense. Free renewals could be profitably adopted b\- all stations instead of a reduction of rates. With free renewals, one of the following- methods should he adopted: 1. Periodicalh’ remove all lamps from the circuits one to four times per \-ear, according to conditions, and rejdace them by new ones. Photometer the lamps removed and save those measuring above a prescribed limit (say 13 c.p.) for use at high voltage points, or locations where reduced candle-power is of slight importance. Scrap the remaining lamps. 2. ('ii\-e a new lamjr in exchange for an old one for, sa}-, ever\- S3. 00 worth of current supplied, or fm- any fi.xed amount determined hv the meter rates and conditions. The second plan is an excellent one, in that it offers a bonus for the use of current and regulates renewals on the correct basis of number of hours of lamp ser\-ice. It can be profitably adopted wherever meters are in use. A station attendant should visit customers C|uarterl)' and install the number of new lamps due each, removing and returning to the station an equal number of old lamps. If station attendance is limited, the lighting company can fill out and mail to their customers, each quarter year, blanks similar to the following. Office of ELECTRIC LIGHT COMPANY Due to Mr. J90 16 candle-power lamps, on the return of an equal number of dim lamps, for the quarter year ending which is on the basis of one lamp for every $3.00 of current supplied. Present this Slip at the Station, or Office. 97 GENERAL ELECTRIC COMPANY In cases where lamps must be charged for, some measures should be adopted to induce customers to renew their dim lamps: as, otherwise, dim lamps will be con- tinued in service as long as they will burn. A good method is to offer new lamps in exchange for dim ones (not burned out) at a reduction in price of one-quarter or one-half cost. A customer, for e.xample, would save b}' jiaA'ing, sa)', half-price for the renewal of a dim lamp, instead of waiting and paying full price when the lamp burns out. Another method is to offer lamps for renewals at less than cost, say 1 5 cents each, and reserve the right to sa}' when lamps shall be renewed. Such a plan works well, as no customer can justly complain when the company renews lamps at less than cost. The price of lamps to the customer in anv case should be made as low as possible — cost price or below cost — for the reason that profit on the sale of lamps is secondary in importance to the sale of current and improvement in quality of lighting service. High charges and illiberal methods in sale or suj^pb' of lamps invariably deteriorate the lighting service for the following reasons : 1. Customers are induced to purchase cheap lamps from outside parties, and therefore use a low grade of lamps. 2. Customers tend to retain lamps in ser\ice as long as they will last, and thus load up the circuits with numbers of old and dim lamps. Every station should have some system of lamp renewals, which will not depend ujion the customer, and which will limit the average life of the lanqis to within 600 hours. 9S GENERAL ELECTRIC COMPANY POINTS TO BE REMEMBERED I'hat a constant in'cssiirc at tlie lamps must he maintained. That the lamps are not to he used to the point of breakage — the\' should he renewed when the)' hecome dim. That satisfaction to customers, and the success of electric lighting is dependent upon good, full and clear light, which old, hlack and dim lamps cannot gi\'e. That to furnish a good, full and clear light is as much a part of the Lighting Compan)''s business as to sujiph' current to light the lamps. That a compan\' should always endeavor to keejithe average life of lamps within 600 hours. That to renew tlim lamps jiroperlv on the tree renewal system, inspectors should e.vamine the circuits regularly when the lamps are burning. If lamp renewals are charged to customers, induce them to e.xchange their dim lamps. FAULTS IN INCANDESCENT LAMPS RAPID LOSS OF CANDLE-POWER Rapid loss of candle-i^iower is a defect in incandescent lamps, although as we ha\'e shown all lamps suffer a gradual loss of candle-power as they are used. A very rajud loss in candle-power is, however, a real fault, due to inc.xperienced manufacture, or use at excessive x'oltage. The remedy is to purchase only lamps of standard reputation produced by the experienced manufacturer and to maintain the pressure at normal on the lamps. The pressure should be carefully tested with accurate portable instruments at the lamp sockets, and if found high, the pressure should be regulated to accord with the 99 < ILLUMINATION OF OMAHA EXPOSITION GROUNDS— GRAND COURT, EAST END GENERAL ELECTRIC COMPANY voltage of lamps, or lamps supiilied to accord with the jiressure. BLACKENING OF BULBS Another defect in incandescent lamps is the blackening of bulbs, although this is more often a supposed defect than a real one. A lamj) may lose in candle-power and show but little black- ening, and on the other hand, a lamp may get quite black and lose little in candle-power. Thus a 50 \'olt lamj) which has a more stable filament than the no volt lamp often shows considerable blackening with little loss of candle-power. Blackening in good lamps results from either high pressure or e.xcessive life. This is a supposed fault. The best of lamps, if burned too long, will always show a certain amount of blackening. The remedies are, of course, reg- ulation of pressure and frequent renewals. The above are the most important defects to be found in incandescent lamps. GENERAL ILLUMINATION The subject of illumination has been divided by Mr. E. L. Elliott, to whom we are indebted for many suggestions, into the following sub-divisions: Intensity or Brilliancy, Distribution, Diffusion and Quality. INTENSITY OR BRILLIANCY The average brilliancy of illumination required will depend on the use to which the light is put. “A dim light that would be very satisfactory for a church would be' wholly inadequate for a library and equally unsuitable for a ballroom.” lOI GENERAL ELECTRIC COMPANY The illumination t;-iven by one candle at a distance of one foot is called the “candle-foot” and is taken as a unit of intensity. In general, intensity of illumination should nowhere be less than one candle-foot, and the demand for light at the present time quite frequently raises the brilliancy to double this amount. As the inten- sity of light \'aries inversely with the square of the distance, a i6 candle-power lamp gi\'es a candle-foot of light at a distance of four feet. A candle-foot of light is a good intensity for reading purposes. Assuming the i6 candle-power lamp as the standard, it is generally found that two i6 candle-power lamps per 100 square feet of Hoor space give good illumination, three very bright, and four brilliant. These general figures will be modified by the height of ceiling, color of walls and ceiling, and other local conditions. The lighting effect is reduced, of course, b}' an increased height of ceiling. A room with dark walls requires nearly three times as manv lights for the same illumination as a room with walls painted white. With the amount of intense light available in arc and incandescent lighting, there is danger ( f e.xceeding “the limits of effective illumination and producing a glaring intensity,” which should be avoided as carefully as too little intensity of illumination. DISTRIBUTION OF LIGHT Distribution considers the arrangement of the various sources of light and the determination of their candle-power. The object should be to “secure a uniform brilliancy on a certain jdane, or within a given space. A room uniformly lighted, even though comparati\'ely dim, gives an effect of much better illumination than where there is great brilliancy at some points and comparative 102 GENERAL ELECTRIC COMPANY darkness at others. Tlie darker parts, e\'en thoug-li actually light enough, appear dark b)' contrast, while the lighter parts are dazzling. For this reason naked lights of any kind are to he avoided, since they must appear as dazzling points, in contrast with the general illumination.” Dining Room of the Hotel Marlboro, New York The arrangement of the lamps is dependent very largely upon e.xisting conditions. In factories and shops lamps should be placed o\’er each machine or bench so as to give the necessary light for each workman. In the lighting of halls, public buildings and large rooms, e.xcellent effects are obtained by di\’iding the ceiling>'s into squares and placing a lamp in the center of each square. The size of square depends on the height of ceiling and the intensity of illumination desired. Another excellent method consists in placing the lamjxs in a border along the walls near the ceiling. GENERAL ELECTRIC COMPANY For the illumination of show windows and display effects, care must be taken to illuminate by reflected light. The lamps shcmld be so jflaced as to throw their rays upon the displa)’ without casting any direct rays on the observer. The relati\'e \-alue of high candle-power lamps in case of an equi\ alent number of i6 candle-power lamps is worthy of notice. Large lamps can be efflcientlv used for lighting large areas, but in general, a given area will be much less effective!}' lighted by high candle-power lamps than an equivalent number of i6 candle-power lamps. For example, sixteen 64 candle-power lamps distributed o\'er a large area will not gi\'e as good general illumination as sixty-four 16 candle-power lamps dis- tributed over the same area. 1 1 igh candle-power lamps are chiefly useful when a brilliant light is needed at one point, or where space is limited and an increase in illuminating effect is desired. DIFFUSION OF LIGHT “ Diffusion refers to the number of rays that cross each point. The amount of diffusion is shown by the character of the shadow. Daylight on a cloudy day may he considered perfectl}- diffused: it produces no shadows whatever. The light from the electric arc is least diffused, since it emanates from a very small surface; the shadows cast by it have almost perfectly sharp outlines. It is largelv due to its high state of diffusion that daylight, though vastly more intense than any artificial illumination, is the easiest of all lights on the eyes. It is a common and serious mistake, in case of weak or overstrained eyes, to reduce the intensit}’ of the light, instead of increasing the diffusion." 104 GENERAL ELECTRIC COMPANY QUALITY OF LIGHT “Aside from difference in intensity, light produces many different effects upon the optic neryes and their centers in the brain. These different impressions we ascribe to difference in the quality of the light. Thus ‘hard light,’ ‘cold light,’ ‘mellow light,’ ‘ambient light.’ etc., designate yarious qualities. Ouality in light is e.xactly analogous to timbre or quality in sound, which is likewise indepemlent of intensity. The most obx'ious differences in quality are plainh' those called color. But color is by no means the onh' element of quality. The proportion of inyisible rays and the state of diffusion, are highly impor- tant factors, but on account of not being directly yisible, they ha\'e been generall}' oyerlooked, and are but imper- fectly understood.” RELATIVE VALUE OF ARC AND INCANDESCENT LIGHTING Arc and incandescent lamps hayeeach their separate fields of usefulness. Incandescent lamps haye the adyantage that they can be distributed so as to ayoid the shadows necessarily cast by one single source of light. For large rooms with space not seriously obstructed by pillars or machines, arc lamps, especially those of the enclosed type, haye an adyantage. A correctly lighted room frequenth’ requires both arc and incandescent lights, the arc for general illumina- tion and the incandescent for near at hand lighting. A good method of comparing illuminating yalues is afforded by the area in square feet a lamp will illuminate. One 1 6 candle-power incandescent lanqi for eyery fifty GENERAL ELECTRIC COMPANY square feet of floor space gives good illumination. One full 450 watt enclosed arc lamp will illuminate an area of 600 or 800 square feet. Nine 50 watt 16 candle-power lamps, consuming the same power as one arc will illuminate a little more than half the area. The efificiency of arc lamps on this basis is, therefore, not greater than two to three times that of incandescent lamps. It has been found that unless an area is so large as to require 200 to 300 incandescent lights distributed over it, arc lamps requiring equal total power will not light tbe area with as uniform brilliancy. of THE CORRECT USE OF LIGHT HOW TO AVOID HARMFUL EFFECTS ON THE EYES An objection frequently urged against the incandescent lamp is that it is harmful to the eyes and ruins the sight. This is true only in so far as the lamp ma)' be improjierh' used. Any form of light as frequently misused would produce the same harmful results. Few people think read by an unshaded oil lamj), to will sit in the glare of a clear glass attempting and yet many incandescent lamp. Incandescent lamps are more generally complained of because, unlike oil or gas, they can be used in any position. Tookkeejiers and clerks are often seen with an incandescent lamp at the end of a drop hanging directly in front of their eyes — an impossible jiosition of the light from gas or oil. The first hygienic consideration in artificial lighting is to a\'oid the use of a single bright light in a poorly illuminated room, In working under such' a light, the GENERAL ELECTRIC COMPANY eve is adapted to the surroundino' darkness and yet there is one spot in the middle of the eye that is kept constantly fixed on the very bright light. The brilliancy of the single light acting on the eye adjusted to darkness works harm. 'I'here should be a general illumination of the room in addition to any necessary local light. If sufficient general illumination is jirovided, the eye is adjusted to the light, and the local light can be safely used. The ideal arrangement provides general illumina- tion so strong that a pencil placed on the page of a book casts two shadows of nearly equal intensity — one coming from the general light and the other from the local light. Care should also be taken to prevent direct rays from striking the eye. The light that reaches the eye by day is always reflected. In reading or writing, to avoid shadows, the light should come over the left shoulder. Only the reflected rays can then reach the eye. Another point to be avoided is the careless general use of clear glass, unshaded lamps. Frosted bulbs should be used in place of clear glass where soft light for reading is required. The intensity of light reflected from a small source is increased, and intense light injures the eye. With a clear glass globe the whole volume of light proceeds directly from the small surface of the lamp filament. With a frosted bulb the light is radiated from the whole surface of the bulb and while the total illuminating effect is practically undiminished, the light is softened by diffusion to the great comfort and relief of the eyes. Finally, the use of old, dim, and blackened lamps giving but a small fraction of their proper light is very often a source of trouble in not supplying a sufficient 107 GENERAL ELECTRIC COMPANY quantity of light. Users of lamps are not often aware of the loss in candle-power a lamp undergoes and so it happens that lamps are retained in use long after their efficient light-giving power has vanished. Proper attention to lamp renewals on the part of central stations is necessary to correct this evil. The correct use of light requires : That there should be general illumination in addition to the light near at hand. That only reflected light should reach the eye. The light should be so placed as to throw the direct rays on the book or work and not in the eye. That the light should be placed so that shadows will not fall on the work in hand. That shades and frosted bulbs should be used to soften the light. That lamps be frequentl}’ renewed to keep the light up to full candle-power. In the Dining Room of the Hotel Savoy, New York r t t I Of INDEX THE MANUFACTURE OF INCANDESCENT LAMPS .... 6 THE SELECTION OF LAMPS 12 THE PROPER USE OF LAMPS J6 STANDARD 50 VOLT INCANDESCENT LAMPS: 4, 6, 8, and lO CandIc-p>ower 22 I 6, 20, and 24 Candle-power 24 32 Candle-power . . . . . . 26 50 Candle-power . . . . . ,28 100 and J50 Candle-power , , 30 STANDARD 100 TO 125 VOLT INCANDESCENT LAMPS: 4, 6, 8, and 10 Candle-power 32 1 6 Candle-power 34 32 Candle-power . . . . . . . . . . . , ,36 50 Candle-power 38 100 and 150 Candle-power .......... 40 Street Railway Lamp ,,,. 41 SPECIAL INCANDESCENT LAMPS : 200 to 250 Volt Lamps 46 Round Bulb Lamps . . . 48 Tubular Lamps 50 Stcreopticon Lamps 52 Edison Night Lamp 54 Resistance Lamp . . . . , .56 MINIATURE INCANDESCENT LAMPS AND APPLIANCES: Candelabra and Decorative Lamps . . . . . . , . .61 Regarding Series Lamps . 63 Series Candelabra Lamps 65 Multiple Candelabra and Sign Lamps 67 Special Series Lamps . , .68 Receptacles and Sockets , 73 Shades for Miniature Lamps ..........75 Battery Lamps . . . .77 Stick-pin and Watch-charm Lamps 82 Examination Lamp for Storage Battery ........ 83 APPENDIX OF INFORMATION ON INCANDESCENT LAMPS: Life and Candle-power of Lamps 86 The Importance of Good Regulation 89 The Measure of a Lamp's Value 95 Incandescent Lamp Renewals . . , . . . , . . .96 Points to be Remembered 99 Faults in Incandescent Lamps . 99 General Illumination . . . . . . , . , . . .101 Relative Value of Arc and Incandescent Lighting 105 The Correct Use of Light 106 no I MAIN LAMP SALES OFFICES. HARRISON, N. J. GENERAL ELECTRIC COMPANY Sales Offices : BOSTON, MASS., 200 Summer Street. NEW YORK. N. Y., 44 Broad Street. Syracuse, N. Y., Sedgwick, Andrews & Kennedy Big. Buffalo, N. Y., Ellicott Square Building. PHILADELPHIA, PA., 509 Arch Street. Baltimore, Md., 227 E. German Street. Pittsburg, Pa., 502 Tradesmens Bank Building. ATLANTA, GA., Equitable Building. New Orleans, La., 917 Hennen Building. CINCINNATI, OHIO, 420 West Fourth Street. Columbus, Ohio, 14 North High Street.! Nashville, Tenn., Room 73, Cole Building. CHICAGO, ILL., Monadnock Building, Detroit, Mich., 704 Chamber of Commerce Big. St. Louis, Mo., Wainwright Building. Dallas, Texas, Scollard Building. Helena, Mont., Electric Building. Minneapolis, Minn., PhoenixJBuilding. DENVER, COLO., Kittredge Building. Salt Lake City, Utah, Templeton Building. SAN FRANCISCO, CAL., Claus Spreckels Building. Portland, Ore., Worcester Building. Los Angeles, Cal., Douglas Building. For aM Business outside the United States and Canada: Foreign Dept., Schenectady, N. Y., and 44 Broad Street, New York, For Canada, address Canadian General Electric Company, Ltd., Toronto, Ontario. Principal Offices, Schenectady, N. Y. MAIN LAMP SALES OFFICES. HARRISON. N. J.