THE ELECTRIC “SUN” LAMP 
 
 and portable parabolic reflector, 
 
 For Photographic Work. 
 
 (BOARDMAN’S PATENT). 
 
 The Price of the 
 25-AMPERE 
 
 HAND-LIGHTING i|||| _ 
 LAMP, PORTABLE 
 REFLECTOR, 
 and STAND, is 
 £15. 
 
 RESISTANCE 
 FRAME, SWITCH 
 and FUSE, 
 £5. 
 
 THE LAMP 
 and 
 
 PORTABLE 
 REFLECTOR 
 can be made for 
 suspending* 
 from Ceiling 
 at same price, 
 £15. 
 
 I N this Lamp the Light obtained is almost identically similar to that of diffused daylight. 
 
 An extract from a discussion on a Paper read by Mr. Trotter to the Institute of 
 Electrical Engineers, says : — “ It was found that the light from the Electric Sun Lamp, with 
 “ suitable Reflectors and diffusing screens, was as nearly as possible the same as diffused 
 “ daylight in a room; there was very little difference in the spectrum of the light from this 
 “ Lamp and that of diffused daylight.” 
 
 The Lamp, as shown in the illustration, is hand-feeding ; but will burn without attention 
 for at least 15 minutes. Automatic Lamps are also made when desired; but the Hand- 
 Lighting Lamps have been found to answer the purpose equally as well, and are of much 
 lighter construction. 
 
 The Portable Parabolic Reflector, when in use, is 4 feet 6 inches in diameter, and is 
 collapsible into the size of an ordinary carriage umbrella. It will be noticed that the interior 
 of the Reflector is quite free from any ribs or stretchers, thus presenting a perfectly even 
 surface, hitherto only obtained by the cumbrous and expensive non-collapsible Reflectors. 
 
 A large number of experiments have been carried out both on the Lamp and on the 
 Reflector for use with the same, and the form as shown in the figure has been found to be 
 most suitable for photographic purposes. 
 
 One of the Lamps can be seen in action at the Works of the Company. 
 
 Testimonial from ALFRED ELLIS, Esq. 
 
 20, Upper Baker Street, London, N.W. 
 
 To the Nalder and Harrison Construction Syndicate, Limited, 16th January, 1895. 
 
 4 7, Victoria Street, S.W. 
 
 Dear Sirs, — I am pleased to inform you that the automatic Electric “ Sun ” (Photographic) Lamp, 
 supplied to me some fifteen months ago has given me entire satisfaction. 
 
 One great feature of Boardman’s Patent Photographic Apparatus I have specially noted is the 
 Collapsible Parabolic Reflector, the portability of which is a very great advantage. 
 
 I have much pleasure in sending you an order for two Hand-lighting Electric “Sun” Lamps and 
 apparatus complete, which please deliver as early as possible. Yours faithfully, 
 
 ALFRED ELLIS. 
 
 NALDER h HARRISON CONSTRUCTION SYNDICATE, Limited. 
 
 Please address all communications to the 
 
 Head Office: 47, VICTORIA STREET, LONDON, S.W. 
 
 dibs ©fftce : Tllflorfts : 
 
 33, OLD BROAD STREET, E.C, bow COMMON lane, London, e 
 
 Telegraphic Address: (Head Office ' — 
 
 “LUCIMTERS, LONDON.” 
 
 f 47, VICTORIA STREET— 3,298. 
 Telephone,— 133 ^ EE0AD ^ _ u m 
 
PHCENIX 
 
 DYNAMO ELECTRIC MANUFACTURING CO, 
 
 "fi/eetrieaf 'ongineerd. 
 
 HUBERT STREET, LEEDS ROAD, BRADFORD. 
 
 — Makers of all kinds of — 
 
 ELECTRICAL MACHINERY 
 AND APPARATUS. 
 COMPLETE INSTALLATIONS, 
 ENGINES, DYNAMOS, SWITCHES, 
 RESISTANCES, LAMPS, 
 
 For Electrical purposes of 
 all kinds. 
 
 AUTOMATIC AND HAND-FED 
 PORTRAITURE SETS, 
 AUTOMATIC, COPYING, PRINTING 
 AND ENLARGING LAMPS. 
 
 Inverted Arc Lamp 
 
 and Reflector 
 Set £15 10s. 
 
 Complete with Switches, Resistance 
 and Suspension or Stand, delivere 
 at Works 
 
 Conical 
 
 Reflector 
 
 SET COMPLETE: 
 
 HAND-FED £15. 
 
 AUTOMATIC .. £25. 
 
 s 
 
 S 
 
 Swinging Lamp. 
 
 All made under the direct supervision of Mr. RANKIN KENNEDY. 
 
 MAKERS OF RANKIN KENNEDY’S SPECIALITIES. 
 
 SEND FOR QUOTATIONS. 
 

 
 
 
PHOTOGRAPHIC 
 
 — AND — 
 
 OPTICAL 
 
 Electric Lamps. 
 
 Rankin Kennedy, 
 
 Electrician anl> Engineer. 
 
 Author of “ Electrical Distribution by Alternating Currents ” and “ The Scientific 
 Study of Arc Lamps,” <pc. 
 
 A Treatise for Photographers, Photo-Electric Printers’ 
 Etchers and Engravers, 
 
 And including Apparatus for Copying Purposes for 
 Engineers and Architects. 
 
 (59 Illustrations). 
 
 LONDON : 
 
 H. ALABASTER, GATEHOUSE & CO., 22, Paternoster Row. 
 
 1895. 
 
 (ALL RIGHTS RESERVED.) 
 
 XX YAN NOSTRAND COMP AN *, 
 
 NEW YORK. 
 
THfe GETTY Ct 
 
 LIBRARY 
 
PREFACE. 
 
 Electricity being now available to many Photographers , <£c., 
 and no work treating on this special subject being in existence , 
 the author has ventured to put together brief descriptions of apparatus 
 and lamps , in the hope that it will meet an oft-expressed want 
 for a hand-book on the subject , placing descriptions and illus- 
 trations of the apparatus before the Photographer and Optician 
 as it now stands. 
 
 Bradford, 
 
 March 25th , 1895. 
 
INDEX 
 
 TAGS 
 
 Ammeters and Voltmeters 7 
 
 Arc and Carbons, On the 55 
 
 Artificial Light for Photography to Resemble Daylight 17 
 
 Automatic Portraiture Lamps 41 
 
 „ „ “ Sun ” Lamp 41 
 
 „ ,, Clutch Lamp 42 
 
 „ „ Pilsen Lamp 44 
 
 „ „ Adamson’s Apparatus 45 
 
 „ ,, with Jablochkoff Candles 46 
 
 „ ,, with Welsbach Burners 47 
 
 „ ,, Another Form of Clutch Lamp 47 
 
 Carbons, giving proper Sizes for different Continuous Currents 56 
 
 Copying Lamps 49 
 
 „ „ for printing Photographic Negatives 51 
 
 „ „ for enlarging Photographs 52 
 
 Electric Re-Touching 54 
 
 Electricity Supply 5 
 
 Gas Photo Apparatus 52 
 
 „ „ Kennedy’s 53 
 
 Lamps and Lamp Regulators 21 
 
 Lamps— Verity’s Hand Fed 21 
 
 „ The Author’s 22 
 
 „ The Author’s, for portraiture work 22 
 
 „ Borland’s Hand-feed Scissors Lamp 24 
 
 ,, Joel’s Hand-fed Photo Lamp 24 
 
 „ Joel & Co.’s Automatic Lamp 25 
 
 „ Davenport Lamp 25 
 
 ,, Davenport Lamp, instructions for 27 
 
 General Electric Co.’s Photo Lamp 58 
 
 „ Jablochkoff Candle 28 
 
 ,, To make the Hand-fed Lamp Automatic 28 
 
 „ Borland’s Automatic “ Scissors ” 29 
 
 ,, Planet 30 
 
 „ Newtonian 31 
 
 „ „ Voltage and Current ... 33 
 
 „ „ Added Resistance in Circuit 33 
 
 ,, Table of Resistance for Various Voltages and Currents 33 
 
 „ Pilsen Joel Arc Lamp 35 
 
 „ Crompton Pochin Arc Lamp 36 
 
 „ Kennedy Hanging Arc Lamp 37 
 
 „ Horizontal Lamp 39 
 
 Photographers’ Electric Pencil 54 
 
 Reflecting Screen and Lamp on One Stand 20 
 
 Reflectors 12 
 
 „ Coating of 14 
 
 „ Conical Zinc 15 
 
 „ Plane Cone 16 
 
 ,, Shape 13 
 
 „ Size 13 
 
 Umbrella 15 
 
 Resistances — Verity’s 8 
 
 „ W. T. Glover & Co.’s 10 
 
 Re-Touching Device, operating the 54 
 
 Search-Light Lamp (Crompton & Co.’s) ... 19 
 
 Table of Manganin, Bare, and Silk-Lapped High-Resistance Manganin 
 Wire 11 
 
Photographic and Optical 
 Electric Lamps. 
 
 BY RANKIN KENNEDY. 
 
 Chapter I. 
 
 T |!HE INTRODUCTION of Electricity into towns and 
 cities for electric lighting has placed within the reach 
 of many photographers the use of electric light for photo-work, 
 printing, enlarging, copying, and other purposes. 
 
 Electric light is also used by photo-etchers in photo-zinco- 
 graphy, and in copying engineers’ and architects’ plans from 
 tracings, &c. Yet there is no work treating specially of this 
 class of apparatus which would be found useful as a guide to 
 photographers, who, as a rule, are not fully acquainted with 
 Electricity and Electric Lamps. 
 
 The author has had many years’ experience with Electric 
 Lamps as used in every kind of photographic work, and has 
 originated many improvements in them. It is the object of this 
 little work to show the various successful lamps and appliances, 
 to describe in simple language the scientific principles upon which 
 they are based, to point out fallacies in regard to their use and 
 abuse, and to give a general idea of the working of each different 
 kind of apparatus. 
 
 First, we may say a few words about the electricity supplied 
 in towns, from which supply, photographers must draw their 
 current. Unfortunately for electrical engineers and photographers, 
 the supply of electricity differs greatly in different places, so that 
 an apparatus made and found successful in one district may be 
 an utter failure in another. Hence we must carefully note the 
 kind of supply available for the apparatus before purchasing or 
 constructing it. 
 
 Electric current supply is broadly divided into two kinds — 
 continuous and alternating. The alternating supply is again divided 
 
6 
 
 into about half-a-dozen different kinds, distinguished by what is 
 known as their frequency. For instance, in the City of London 
 we have an alternating current supplied at a frequency of 100 per 
 second — it pulsates at the rate of 100 per second ; in the Strand 
 district and other places we have a supply at a frequency of 82 
 per second, and in the Holborn district we find another supply 
 at 133 per second. 
 
 This diversity seems a most extraordinary thing, and it is 
 certainly a reflection against the whole body of electrical engineers 
 that such differences should have sprung into existence, causing, 
 quite unnecessarily, great inconvenience, expense, and trouble. 
 For there is no earthly reason why the frequency should not be the 
 same all the world over if electrical engineers would only agree 
 among themselves to use one common frequency. This could 
 have been as easily done as it was easy to agree upon a standard 
 Ohm, Yolt, or Ampere unit. Unfortunately no agreement was 
 made, and a number of supplies are laid on, in which the 
 frequency cannot now be altered. 
 
 The photographer uses principally the arc-lamp, and this 
 lamp hums disagreeably in unison with the pulsations of the 
 alternating current. This often forms an objection to alternating 
 currents for arc-lighting, especially in portraiture, where it is apt 
 to disturb the sitter. The author invented an apparatus for 
 the purpose of converting alternating into continuous current, 
 and thereby enabling photographers to obtain the advantages of 
 continuous currents, although they may have the misfortune to 
 be situated in a district supplied by alternating currents. 
 
 The continuous current supplied in different places differs 
 only in pressure. Electrical engineers have stupidly blundered 
 in this respect also, for nothing could have been easier than to 
 agree upon one common pressure of supply, and thereby have 
 made it possible to work the same apparatus anywhere. 
 
 We find pressures supplied at 100, 105, 110, and 120 volts, 
 and on three-wire systems we can get 200, 210, 220, and 240 volts 
 supplied. It would have been infinitely better if all over the 
 world 120 volts were the standard on the two-wire supply, and 
 240 on the three-wire. 
 
 The mischief has been done, however, and is now beyond 
 remedy in many cases. We are compelled, therefore, to enter 
 into the consideration of various changes and devices required 
 to adapt the apparatus to these differing supplies. 
 
7 
 
 Whatever kind of current is supplied, it will come through 
 a meter and be charged at an average price of about 6d. a unit. 
 
 , A unit of electricity is a quantity consumed by an ordinary 
 10 -ampere arc-lamp in two hours’ burning, or consumed in six- 
 teen incandescent lamps, each of 16 candle-power, in one hour. 
 
 The volt is the unit of pressure of supply, and is indicated 
 by a voltmeter. The ampere is the unit of current, and the 
 volume of the current passing through a lamp is indicated by an 
 ammeter. 
 
 The photographer who wishes to make the best use of his 
 electric supply ought to know something of these instruments, 
 so that we shall briefly refer to an example of each of Verity’s 
 make. 
 
 These instruments are represented in Figs. 1 and 2, and in 
 any case an ammeter should be used to know what current is 
 being absorbed in the lamps. 
 
 Both ammeter and voltmeter must be of the dead-beat kind, 
 as an instrument in which the pointer swings about under any 
 slight change is of no use. 
 
 Many instruments sold cannot be read on arc-lamp circuits, 
 owing to this swinging about of the pointer, but plenty of good 
 dead-beat instruments are to be had if insisted upon, costing 
 from £Z to £4. 
 
 It is also important to get instruments for alternating 
 circuits to be correct on the particular circuit on which they are to 
 be used. An instrument all right on one may be all wrong on 
 another circuit of alternating current, and in ordering instruments 
 the frequency of the current should be stated if for alternating 
 circuits, 
 
8 
 
 RESISTANCES. 
 
 Resistances are required to regulate the volts on the lamp 
 terminals, or pressure on the lamp. These resistances consist of 
 spirals of German silver wire, strung on a frame, with a switch, 
 as in Eig. 5, also of Verity’s make. By moving the switch, 
 more or less wire is put in the path of the current on its way 
 to the lamps, and thereby the pressure of the current is reduced 
 and the amount of current regulated. 
 
 Thus, if the supply is 110, and we want only 45 volts on the 
 lamp with 50 amperes current, it is evident we must reduce the 
 pressure by 65 volts. The resistance required to do this is 
 easily found. The unit of resistance is called an Ohm , and the 
 rule is to divide the pressure to be choked back (in this case 
 65 volts) by the current, which in this case is 50 amperes 
 = -|A = 1.3 ohms = the resistance required. 
 
 Or suppose the pressure is 100 volts, and the lamp pressure 
 45 volts, and the current 25 amperes ; here 100 — 45 = 55 volts 
 to be choked off, so that J-f = 2*2 ohms. 
 
 In this way we can readily find what resistances are required 
 to reduce the supply pressure to our requirements. 
 
 Eig. 4 is a diagram of a lamp, a resistance, and a supply, 
 showing the various distributions of the pressure. The figure 
 shows us the last cise calculated : current 25 amperes, total 
 pressure 100 volts, 45 volts in the lamp and 55 in the resistances. 
 
 Now these resistances waste the electricity ! You pay for 
 bhe 100 volts pressure and use only 45. It is better, therefore, to 
 use two lamps in series and get the full use of the pressure you 
 pay for. Eig. 3 is a diagram explaining this double arrangement. 
 
 In Eig. 4, L is the lamp with the voltmeter V, joined 
 
9 
 
 across to show the 45 volts pressure, R is a resistance of 2-2 ohms, 
 with a voltmeter across which would show 55 volts being wasted, 
 and A is an ammeter through which the current passes, and 
 indicates, in this case, 25 amperes. 
 
 In Fig. 3, L L are two lamps connected in series, that 
 is, the one current goes through both, and, as each takes 45 volts 
 of pressure, the two will take 90 volts, as will be seen by the 
 voltmeter V. In this case we have only to waste 10 volts on 
 a 100 volt supply, so that for 25 amperes we want only 
 if = 0*4 ohm resistance for R. 
 
 Fig. 5. 
 
 Fig. 5 is a construction for large resistances, where, for 
 instance, 110 volts are to be reduced to 45 volts, and to carry 
 a current of from 50 to 70 amperes. 
 
 For small resistances a spiral of wire, wound on an enamelled 
 iron cylinder, as shown in Fig. 6, is used. A clamp, made of 
 two half-circular hoops, is connected to one end, so that it may be 
 
10 
 
 clamped on at any place to adjust the resistance to the desired 
 amount. 
 
 No combustible material, on any account whatever, is to be 
 allowed in the construction of resistances. Resistances waste the 
 electric energy by turning it into heat ; they must, therefore, of 
 necessity work hot — sometimes nearly red-hot. 
 
 The wire used for resistances is sometimes platinoid. Tables 
 of its size, weight, and resistance are easily obtained. 
 
 Messrs. Walter T. Glover and Co. have introduced a good 
 material called manganin, a table of which is given. To use the 
 table in selecting a wire for resistances, I have added a column of 
 currents for which the wire is best suited. Thus No. 14 wire 
 will carry from 15 to 20 amperes, so that, supposing we want 
 2 ohms resistance to carry 20 amperes, we should find in the table 
 that a little over 1 lb. weight of this wire would give 2 ohms ; we 
 should find the length of this wire also, and could, therefore, 
 prepare a cylinder or spirals to carry the quantity of wire, 
 
AND SILK LAPPED HIGH RESISTANCE MANGANIN WIRE. 
 
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12 
 
 Resistances must be used with all arc-lamps. A little 
 resistance is necessary to enable them to feed well. One lamp 
 requires, when carrying 20 or 25 amperes, 1 ohm for the 
 20 amperes, and O’ 8 ohm with 25 amperes — in other words, 
 65 volts across both resistance and lamp, 20 in resistance and 
 45 in lamp. 
 
 Many lamps will work with less than a total voltage of 65, 
 but not so well. 
 
 In alternating circuits resistances should be used only for 
 that amount required to enable the lamps to be run steadily. 
 
 Lamps on alternating circuits should never be run in 
 series but always run singly. That being so, the user should 
 always either get his supply from the company at 50 volts, or 
 provide himself with a transformer to reduce the pressure to 
 50 volts. This is important. 
 
 If this is not done, the 50-ampere Lamp would cost for 
 current 2s. 6d. per hour, whereas if a transformer is used the cost 
 will be only Is. 3d , a saving which very soon pays off the <£6 
 or £7 charged as the price of a suitable transformer. 
 
 Alternating lamps run well on a 50-volt circuit, as they take 
 only 35 to 40 volts, leaving 10 to 15 volts for the regulating 
 resistances. 
 
 REFLECTORS. 
 
 We may now consider the subject of reflectors. A very 
 important thing is the reflector when large lights are employed ; 
 not only for economy but also for effect must the reflector be 
 designed. 
 
 The most absurd ideas are prevalent on this subject, and 
 reflectors of the most extraordinary shapes and forms are 
 commonly in use. That any results at all can be got with them 
 is due simply to the extravagant use of very high power arc- 
 lights. 
 
 Some reflectors tested by the author produced fine portraits 
 in less than one second’s exposure with a light of 40-ampere 
 power, while another form of reflector took two seconds with 
 70 amperes, the plates being the same quality in both cases. 
 
 First, then, as to shape of reflectors. We may point out that, 
 as in all cases, dead-white surfaces are used ; they are reflectors 
 only — not mirrors. It is surface only we require, and it might be 
 
a flat disc. In fact, the first exhibition of lighting from reflectors 
 was at the Paris Electrical Exhibition, in 1880, the Art Gallery 
 being then illuminated by Jaspar arc-lamps, in which the arc was 
 concealed and the light thrown on to a large flat white disc from 
 which it was reflected down upon the pictures, producing a fine 
 daylight effect. 
 
 It is necessary to depart from the flat disc in order to catch 
 all the rays, but even then we can still retain a very simple form, 
 namely, a plane, conical shape like that shown in Pig. 9, a printing 
 lamp of the author’s for horizontal hanging, to be described later on. 
 
 The curved form, or umbrella- shape, is bad, expensive, and 
 clumsy, and a test between a conical reflector and an umbrella- 
 shape proves the fact that, while the cone reflected 80 per cent, of 
 the arc-light, the umbrella reflected only 50 per cent. Both 
 reflectors in this test were of the same diameter at the mouth, 
 and such a difference was to be expected from theoretical reasons. 
 
 Size of reflectors is another important point. The general 
 rule is simply thus — the bigger the better. What ridiculous little 
 discs of reflectors we sometimes see on arc-lamps of 20 to 30- 
 ampere power ! Little things under 1 foot in diameter. They 
 may act as screens to keep the light out of the user’s eyes, but 
 they never act as reflectors. 
 
 A 10-inch reflector is big enough for a gas jet or an incan- 
 descent lamp of 16 candle-power, and that is a size commonly 
 used for such small lights, but when we come to collect and reflect 
 lights of from 4,000 to 6,000 candle-power, 10 or 12 inches is 
 absurd as a diameter for a reflector. 
 
 Eor photographing, where the light is to be thrown over a 
 wide surface, the reflector must not be less than 4 feet 6 inches 
 in diameter. 
 
 Eor copying photos or pictures by electric light or for copying 
 plans and other work requiring the light on a smaller surface, 
 more than one light is desirable, and a reflecting surface about 
 3 square feet at least for each light is required. 
 
 For photogravure or zinco-photo work, where only about 1 or 
 2 square feet is usually the surface to be lighted, a chalk reflector 
 and bull’s-eye lense is useful. 
 
 This arrangement is shown in Figure 8, A. The arc is 
 formed in the focus of a parabolic reflector turned out of a lump 
 of chalk, a cube about 5 or 6-inch sides, and bored to pass the 
 carbon rods on two opposite sides. The lamp shown here is 
 
14 
 
 hand -fed ; the lens is built up of concentric rings in a brass 
 frame, and throws a solid beam of light on to the print. The 
 chalk makes an excellent reflector, and stands any amount of heat. 
 
 Coating of Reflectors. — The best coating for photograph 
 reflectors is first a good grounding of white lead, then a few coats 
 of pure zinc white mixed in thin, colourless lacquer. This is the 
 best coating for the large reflectors where the direct light of the 
 arc is screened. 
 
 But in many cases the direct light is desirable, such as for 
 printing and copying. In these cases an iron reflector enamelled 
 white inside, like the now common enamelled household utensils, 
 is the best. 
 
 By a skilfully-designed reflector, carefully calculated in size 
 for its work, a light of 30 amperes can do the work of a 50-am- 
 pere lamp with a small, badly-designed reflector, and the money 
 lost in current in a year would most likely pay for a dozen proper 
 reflectors. 
 
 Of course, such flimsy things as cotton, canvas, or silk 
 umbrella-shaped reflectors are not considered at all here. The 
 author, from experience, knows that only metallic reflectors are 
 durable and safe. Nothing combustible should be tolerated in 
 
15 
 
 photo-electric arc-lamp construction. Fires may be rare from 
 arc-lamp causes, but that is no reason why we should make a fire 
 possible. 
 
 A plane conical zinc reflector is substantial, incombustible, 
 and serves the purpose both mechanically and, as a reflector, far 
 better than the umbrella-shaped, fearful looking affairs used in 
 some cases. 
 
 The photographer who has in 
 use one of these extraordinary 
 shaped large reflectors will find, 
 if he replaces it intelligently by 
 a cone reflector of same diameter 
 at mouth and same depth, that 
 he will get at least 25 per cent, 
 more light, and in some cases 
 50 per cent. more. 
 
 Fig. 7 represents a form of 
 reflector found in many studios. 
 
 The flange, F, is a mysterious 
 affair. What useful purpose it 
 serves one cannot conceive ; it, however adds considerably to 
 the weight and first cost. 
 
 Fig. 8 is another still more extraordinary reflector, in 
 which a diaphragm or stop is fixed on the mouth of a large 
 
 umbrella reflector, reducing it from 
 an opening of 48 inches or 54 inches 
 to 36 inches or 42 inches. 
 
 If the flange, F, in Fig. 8 were 
 silvered and polished, it might be 
 effective in some small degree in con- 
 centrating the light into the crown 
 of the umbrella, and thus increasing 
 the direct light through the aper- 
 ture ; but direct experiment proves 
 that it does not increase the light, 
 and, what is more significant, it 
 does not reduce the light to any 
 appreciable extent — a very striking 
 proof that the sides of the umbrella are useless as a reflector, 
 for F, in Fig. 8, cuts off the light if any is reflected forward 
 from the sides. That it cuts off only a small fraction proves that 
 
16 
 
 the sides reflect only that small fraction in a forward direction. 
 The flange in Figs. 7 and 8 is a sort of freak ; it cannot possibly 
 have any optical, mechanical, or other earthly effect whatever. 
 
 It has been suggested that it is put there as a sort of handle 
 for the operator to grab when he wants to pull the apparatus 
 about. A door-knob would, however, seem to be a cheaper and 
 more effective affair for that purpose. 
 
 No curved or umbrella-shaped reflector can equal the plane 
 cone here shown, Fig. 9, for efficiency as a dead-white reflector ; 
 this is the best form for portraiture work. 
 
 A curved form is all right and proper for a mirror with a 
 polished surface, but for a dead-white or matt surface a plane cone 
 is far superior ; the worst shape of all is a hemisphere, and it 
 ought to be avoided. 
 
 A deep cone is required for alternating current arcs, and the 
 arc should be well up into the cone, about half way in. The cone 
 should be 2 feet deep for alternating arcs, and 16 inches for con- 
 tinuous arcs when it is 4 feet 6 inches wide. 
 
 The continuous current arc may be worked well down, about 
 level with the mouth of the core, and with the positive the lower 
 carbon. 
 
 Fig. 9 . 
 
17 
 
 Artificial light for photography must be made to resemble 
 daylight as much as possible in every way, but more especially in 
 the direction in which light falls ; for this reason large surface 
 reflectors are used. 
 
 In Fig. 10 is illustrated the fall of light from an arc light 
 It falls as a oonical beam and in straight lines from a single point 
 thus producing hard, sharp shadows and profiles, and an unnatural 
 appearance. 
 
 In Fig. 11, we have an arc in a bowl to screen off the direct 
 light which is thrown up on a dead-white reflector, and power- 
 fully illuminates the whole surface. From this surface the light 
 is thrown forward, principally in parallel lines, and also in crossing 
 lines, in every different plane ; this is like daylight, mixed light 
 or diffused light, and gives a photo a beautifully soft, natural 
 appearance. 
 
 B 
 
18 
 
 In Fig. 12 we have the conical reflector, which also gives 
 light, principally falling in parallel lines but crossed by other 
 rays at all angles, thus giving the desired diffusion of the light 
 falling on the sitter. 
 
 Fig. 12. 
 
 How the light falls from the umbrella and other extra- 
 ordinary shaped reflectors is a matter not worth considering here. 
 The problem may be left to the scientific photographers who use 
 
 We may now describe another style 
 of photo-electric plant which has only 
 recently come out. 
 
 A diagram of this method, with 
 one lamp and one screen, is shown in 
 Fig. 13. 
 
 S is a light, portable canvas screen, 
 pure white on surface, and with a fold- 
 ing top wing to throw light downwards ; 
 it may have the dimensions marked 
 in the Fig. 13. 
 
 The lamp should be about 4 feet 
 6 inches or five feet high, and swivel 
 up and down and in every direction. 
 
 The light is thrown on the screen 
 and from thence upon the sitter. 
 
 With two lamps throwing their 
 light on the screen, and by judiciously 
 placing the screen with relation to the 
 sitter, very fine photographic work can 
 Fig- 13. be executed. 
 
 them. 
 
19 
 
 This plant is entirely portable, and can be stowed away 
 when not required. The lamps and reflector being separate, 
 much more variety of work can be done, and a clever operator 
 working with two screens and two lamps can produce artistic 
 effects hitherto unapproached. 
 
 The Sun Lamp and many other lamps are suitable for this 
 class of work. But perhaps the best type of lamp for the purpose 
 is a search-light lamp like Crompton and Co.’s (Fig. 14), mounted 
 
 on a universal stand, and with an enamelled iron bowl to screen 
 the light from the sitter and throw it on to the movable white 
 reflector screen. There is very little mechanism in it and that of 
 the simplest. Its steadiness is quite unaffected by the move- 
 ments of the projector, in fact it will burn equally well in any 
 position. By turning the star nut shown in the illustration the 
 lamp may be converted from an automatic lamp to a hand lamp, 
 the feed being then effected by the milled head screw. By 
 means of this star nut the automatic motion is disconnected both 
 electrically and mechanically. The thumb-screw, which acts on 
 the feeding mechanism, is for adjusting the length of the arc. 
 
 b 2 
 
20 
 
 It is as well to make the lamp-stand telescoped to rise and 
 fall, and the lamp to swivel. 
 
 This method of photo work is by far preferable to swinging 
 lamps, and has much to recommend it to photographers. 
 
 Another modification of the method worked out by the 
 author is to have the reflecting screen and lamp on one stand. 
 This is very good for small studios — is cheap and effective. The 
 lamp is an inverted lamp of ordinary make, with a conical 
 reflector, as shown in Fig. 15. A plane reflector 3 feet 6 inches, 
 
 or 4 feet in diameter, if circular, or the same size square, is 
 pivoted on a light, rectangular frame ; this reflector is of dead- 
 white surface, and can be angled to produce various effects. A 
 painter’s canvas stretched on the usual frame makes a very 
 good reflector for this purpose and is perfectly safe in this case, 
 as the lamp is below it. 
 
 The method of employing a separate portable lamp and 
 reflector, as shown in Fig. 13, is one which is bound to come into 
 favour, as it gives the photographer entire freedom in manipula- 
 ting his lights. 
 
21 
 
 Chapter II. 
 
 LAMPS AND LAMP REGULATORS. 
 
 Some lamps have no regulators, being hand-fed. The carbons 
 burn away, and as they burn silently and with a maximum of 
 light when maintained at one constant distance apart, it is im- 
 portant that the mechanism of the lamp should properly effect 
 this continually feeding forward of the carbon as it burns away. 
 When the feeding is by hand, the mechanism is usually a pair of 
 
 screws, one right, the other 
 left, as shown in Fig. 16, 
 one of Verity’s. By turn- 
 ing the hand-wheel at the 
 lower end of the screws, 
 the carbon - holders are 
 moved towards or away 
 from each other, so that 
 by this simple means the 
 length of the arc can be 
 readily adjusted. 
 
 This construction is 
 massive and calculated for 
 large currents of from 50 
 to 100 amperes, and it is 
 generally mounted in front 
 of a mirror for projecting 
 the light forward in a 
 straight beam, and is used 
 for search lights in the 
 army and navy. 
 
 For most photographic 
 and optical purposes a 
 small, cheap hand-fed lamp 
 is all that is necessary, as 
 hand-fed lamps are only 
 used for temporary pur- 
 poses, automatic lamps 
 being preferable for con- 
 tinuous use, 
 
 Fig. 16. 
 
22 
 
 A very simple hand-fed lamp, suitable for lanterns, enlarging, 
 and copying on a small scale, and one which can be constructed 
 by any brass worker for a few shillings, has been designed by the 
 author, and is illustrated in Fig. 17. 
 
 Two guide-rods are fixed in a base-plate, and running easily 
 upon them are the two carbon-holders, A, B, hung over pulleys ; 
 the upper carbon-holder has a spindle, S, guided through a collar 
 on the top plate ; a lever works in a slot in this spindle, and by 
 means of the long end of this lever the carbons can be easily 
 approached or drawn away from each other to regulate the length 
 of the arc. 
 
 Later on I shall describe how to make this into an automatic 
 lamp. 
 
 Fig. 18 is a sketch of the author’s design for a hand-fed 
 lamp for portraiture work ; it also is easily made up of simple 
 materials, and as it is an important apparatus it will be described 
 in full. 
 
 A large reflector is made of zinc for lightness, or of thin 
 tinned iron ; it is 4 ft. or 4 ft. 6 in. in diameter, and about 16 in. 
 deep ; a flange, W, secures the lamp in the crown of the reflector 
 fixed on the main tubes P. This tube is 1^ in. outside diameter of 
 stout brass, and is 30 in. long. At the lower end is carried a 
 carbon-holder, for a 20-millimetre carbon, B, and on the carbon- 
 holder, B, a small enamelled iron bowl is fixed to act as a 
 
23 
 
 reflector, and to screen the direct light from the sitter. These 
 bowls are sold by hardware people for kitchen use at about 8d. 
 to Is. each. 
 
 The tube, P, carries two guiding-eyes, x, y, guiding a f-in. 
 brass tube carrying the upper carbon-holder, which takes a 
 15 -millimetre carbon rod. A cord passes from this tube over a 
 pulley, P, and down to a small winch, K, by means of which the 
 arc can be regulated perfectly. At yds a small pulley on a rocking 
 arm, with sufficient back weight to open the arc. By tipping up 
 the ball smartly with the finger the arc is easily and beautifully 
 struck up without a dangerous rush of current after the arc is 
 struck ; the feeding can be kept up by unwinding the cord from 
 the winch. Normally when no current is passing the two car- 
 bons should be g or in. apart. 
 
 The small hand-fed lamp, Fig. 17, can be used with any 
 current, and up to a power of 70 amperes, and will work down to 
 1 ampere ; it will require from 40 to 45 volts continuous, and 
 28 to 35 volts alternating current. 
 
 The portraiture hand-fed lamp will work also with any 
 current, and takes from 40 to 70 amperes, and a pressure of 40 to 
 50 volts continuous current, and 30 to 40 volts alternating. 
 
 The necessary resistances must be used for each, and found 
 by calculation, as before directed. 
 
24 
 
 Hand-fed lamps are exceedingly handy at times, and a little 
 practice enables one to work them with perfect arcs. They do not 
 get out of order readily, and are cheap. 
 
 Fig. 19 illustrates Borland’s Hand-feed Scissors Lamp — a 
 simple and effective little lamp for lantern work. 
 
 Fig. 19. 
 
 Joel’s Hand-fed Photo Lamp is shown in Fig. 20, with its 
 suspension gear and reflector. 
 
 Fig. 20, 
 
25 
 
 It is made to hand-feed the carbons with an endless screw 
 action, and it is effective and reliable. Messrs. Joel & Co. 
 also make a self-feeding automatic lamp, using the Pilsen core 
 and coils, and this lamp will burn continuously for some six 
 hours, with a steady arc, and in either a horizontal or vertical 
 position. 
 
 The arc-lamp, Fig. 21, has been designed by Mr. Davenport, 
 and is constructed by J. H. Steward for use in the ordinary 
 size optical lantern, such as used for three-wick oil lanterns, 
 without alteration, and, with the back plate modified a little 
 to that shown in illustration, will go into all lanterns having 
 openings at the back. All these hand-fed lamps work 
 centrally, and require no more attention than the limelight — 
 in fact, it is only necessary now and then to turn the milled 
 head of pinion, and bring the top carbon down a little. The 
 bottom carbon is fed automatically, and the point remains in 
 
 Fig, 21. 
 
 ONE-FOURTH ACTUAL SIZE. 
 
 same position as when first adjusted by the slotted mount and 
 clamp screw near the base. The carbons can be quickly changed, 
 but are long enough for an average entertainment. The arc light 
 being of small area enables splendid definition to be obtained ; 
 and for ordinary projection of photographs, microscopical work, 
 and all optical experiments, as well as enlarging, will be found 
 invaluable. As direct or continuous currents of electricity are 
 
26 
 
 now supplied to so many private houses, as well as to nearly all 
 the large halls, institutions, colleges, and societies’ places of 
 meetings, clubs, &c., it is thought that a long-desired want has 
 been supplied, by the facility given to demonstrators, lanternists, 
 and the commercial world, of getting a most brilliant and steady 
 light at a moderate cost, as a first outlay, and little or no expense 
 to lecturer in working where current is on. 
 
 The object sought has been to provide a lamp, simple in 
 design, easily understood, and capable of being used by persons 
 unacquainted with electrical science. 
 
 The lamp consists of two carbon-holders, so arranged that, 
 while the lower carbon is automatically maintained in the proper 
 position for burning by a spring within the lower carbon tube, the 
 upper carbon is fed forward from time to time as the carbon is 
 consumed, by a rod at the back of the lamp attached to a rack- 
 and-pinion arrangement. It will burn about five minutes without 
 attention or any sensible diminution of the light should the 
 operator not be able to turn the rod. 
 
 The tube containing the lower carbon is fastened by a 
 thumb-screw to a fixed upright plate, having a slot cut in it so 
 that the height of the tube may be varied and other adjustments 
 made. The two carbons are set at an angle so that the full benefit 
 of the arc is obtained directly in front. 
 
 The lamp is made of such size and shape that it will fit any 
 ordinary lantern without alteration, thus allowing of the lime- 
 light or other luminant being used when the electric current is 
 not available. 
 
 The rod carrying the pinion for feeding the upper carbon 
 projects at the back of the lantern, and the only attention necessary 
 in using the lamp is to turn this rod from time to time in a similar 
 manner to that required when turning the lime for the lime- 
 light. 
 
 The lamp is perfectly steady in working, and gives a light 
 capable of being varied to a greater or less degree by suitable 
 resistances. 
 
 In all cases where a large disc has to be covered, the greater 
 power of the electric light is a distinct advantage over the lime- 
 light, while its purer colour enables much better results to be 
 obtained. 
 
 For scientific demonstrations, the projection of microscope 
 slides, and for experiments with reflected light, and other purposes 
 
27 
 
 where the loss of light is great, the arc lamp is invaluable, as it is 
 impossible to obtain satisfactory results with any other luminant 
 except on a very small scale. 
 
 The following are the necessary working instructions supplied 
 with the Davenport lamp : — 
 
 The lamp should be worked with from six to eight amperes 
 of current, and requires an electromotive force — E.M.F.— of not 
 less than 60 volts. A resistance should be placed in the circuit, 
 varying according to the E.M.F. employed. 
 
 The amount of resistance necessary may be ascertained 
 approximately, as before described, if the E.M.F. required to 
 overcome the resistance of the arc itself be reckoned at 45 volts. 
 The difference between this E.M.F. and the E.M.F. of the main 
 circuit should be divided by the amount of current in amperes 
 required in the lamp, and the resultant will be the amount of 
 resistance in ohms. Examples : — 
 
 E.M.F. in supply circuit = 101 volts 
 
 101 _ 45 = 56 
 
 Volts. Amperes. Ohms. 
 
 56 4- 7 = 8 
 
 E.M.F. in supply circuit = 59 volts 
 
 59 — 45 = 14 
 
 Volts. Amperes. Ohms. 
 
 14 ^ 7 =2 
 
 All lamps will work much better when the higher E.M.F. is 
 used, with a proportionately higher resistance. 
 
 The positive terminal of the lamp (marked +) should be 
 connected to the positive terminal of the supply circuit, and the 
 negative terminal (marked — ) to the negative or return terminal 
 of the supply circuit. The resistance may be inserted in either 
 the positive or negative portion of the circuit. A fuse should be 
 inserted in the main circuit near the terminals for the lamp 
 supply, capable of carrying about 15 amperes before fusing. 
 
 Wires equivalent to not less than No. 14 B.W.G. should be 
 employed for the branch of the main circuit supplying the lamp, 
 and also for the flexible wires connecting to the lamp. 
 
 Carbons should be 8 m/m. in diameter, cored carbons being 
 used for the upper or positive carbon and solid ones for the lower 
 or negative carbon. 
 
 This lamp can be used for copying and printing on a small 
 scale. 
 
28 
 
 The Jablochkoff candle, as modified by Rapieff, is used for a 
 Photo-Electric Lamp as described later on. Fig. 22 represents 
 this lamp. 
 
 Two carbon rods, inclined to each 
 other, are drawn apart when the current 
 passes, and so form the arc ; they are 
 specially suited for alternating current 
 working, and, by exercising a little 
 care, can also be used in continuous 
 current circuits by manipulating a 
 reversing switch every five minutes. 
 
 The Jablochkoff candle can also 
 be used for lantern work, enlarging 
 and other purposes in the form shown 
 in Fig. 23. 
 
 The coil of wire in front keeps the 
 arc always at the tip of the candle, and 
 the candle can be pushed through the 
 holders as it burns away. The current 
 must pass through the coil and arc in 
 series. 
 
 An oblong coil laid alongside of 
 the candle is sometimes used to keep the arc to the point, but no 
 coil is needed if the candle is slightly tipped up so that the arc is 
 the highest point. An angle of 30° with the horizontal is sufficient. 
 
 To make the small hand- 
 fed lamp automatic it is only 
 necessary that the lower carbon- 
 holder should carry an iron cone, 
 I, which may be of the double- 
 tapered form — that is, it has 
 about 1^ in. plain in the middle, 
 
 and tapers to both ends to a 
 point an g in. diameter or T 3 g in. 
 The middle 1| being J-th iron, 
 the two bobbins, A and M, are 
 formed on a vulcanised fibre rod, 
 about J-th inside bore, by fixing 
 on four flanges 3 inches apart. 
 The tapered core is carried in 
 a thin brass tube fixed to the lower carbon-holder A. A is the 
 
 Fiff. 23. 
 
29 
 
 fine wire shunt coil which feeds the carbons together, and should 
 consist of No. 30 B.W.G. single cotton-covered copper wire, 2 lbs. 
 
 being enough. The bobbins should be 
 about 3 inches outside diameter. 
 
 The thick wire, bobbin, M, is wound 
 with cotton-covered copper wire of a size 
 to carry the current for which the lamp 
 is wanted. Five layers of No. 10 B.W.G. 
 will do for 15 to 20 amperes ; for a 
 lantern-lamp of 8 to 10 amperes, No. 14 
 wire, in 8 layers, will do. 
 
 The upper carbon-holder has to be 
 weighted until the carbons just move 
 together by their weight ; the construction 
 is obviously simple, and the main current 
 passes through the thick wire and then 
 on to the lamp-frame. 
 
 The upper carbon-holder is insulated 
 from its carrier and connected to the 
 other terminal by a flexible wire, F. 
 The shunt is connected across the two 
 terminals, all as shown in Fig. 24. 
 
 Another simple automatic optical 
 lamp is that by Borland, of Leeds, 
 known as the “ Scissors ” Lamp, shown in Fig. 25. Cores 
 working on the short end of the levers open or close the arc, and 
 
 Fig. 25 . 
 
30 
 
 the arrangement is exceedingly simple and goes into a small 
 lantern easily ; it works with continuous current, and can be made 
 also for alternating current. We now come to the 
 
 PLANET LAMP. 
 
 This lamp is an excellent design of an automatic arc-lamp fed 
 by screw and motor gear. It is not an entire novelty in arc-lamp 
 mechanism. 
 
 A lamp for scenic purposes must be simple and reliable, and 
 be capable of working in the most unskilled hands, and, most 
 important of all, should have no loose parts to dangle about when 
 the lamp is inclined ; in fact, the mechanism should work equally 
 well whether it stands upright, is inclined to any angle, or laid on 
 its side. 
 
 The Planet lantern-lamp appears to meet these requirements, 
 so far as a continuous current lamp is concerned, but we are not 
 informed whether the lamp can be used for alternating currents 
 or not. 
 
 The accompanying illustrations show the various parts of the 
 lamp in detail. In Eig. 26 the lamp is shown partly in section, 
 with one field magnet removed. 
 
 Fig. 26. 
 
31 
 
 G + and C — are the positive and negative carbons ; 
 these are proportioned so as to burn at an equal rate. The 
 carbon-holders are arranged to be moved in either direction 
 by the screwed shaft, K, by means of the threaded collars 
 or nuts. The upper and lower portions of the shaft, K, 
 are threaded right and left hand respectively, so that the two 
 carbon-holders always move in opposite directions. The 
 toothed wheel, W, is keyed on to the shaft, K, by the means of 
 the pin and slot, P, which leaves the shaft free to move through 
 a certain distance, in order to adjust the arc vertically to the 
 focus, by moving both carbon-holders simultaneously. This 
 movement is effected by slackening the lock-nut and turning 
 the milled nut in either direction, according as the arc is 
 above or below the focus ; this adjustment does away with the 
 necessity of a separate levelling-table. The armature, A, of the 
 electric motor drives the wheel, W, by means of a small pinion. 
 The field magnets of the motor are wound with several layers 
 of thick wire, through which the current flows to the + 
 carbon by way of the copper guide-rod, B, and sliding-block, D. 
 B and B 1 are metal brushes, through which current is conveyed 
 to the armature coils. S and F are two platinum-tipped screws, 
 which, together with the metal tongue, T, and the soft iron bar, 
 Z, form the relay by which the supply of current to the armature 
 is directed and controlled. By adjusting these two screws the 
 length of arc can be regulated at will. When the tongue, T, 
 touches the screw, F, a small current, derived from part of the 
 resistance passes through the armature, causing it to turn, so 
 as to feed the carbons together ; and when the tongue, T, touches 
 the screw, S, the current is reversed, thereby reversing the 
 direction of the armature, and separating the carbons. 
 
 NEWTONIAN LAMP. 
 
 The Newtonian Optical Electric Lamp is among the latest 
 forms. It is automatic in its action, and has a very perfect 
 and complete movement for hand adjustments ; altogether it is a 
 beautifully-made and well-designed lamp in the various forms. 
 
 The automatic feed is one of great simplicity. It is an abut- 
 ment feed. The ends of the carbons abut against three screws in 
 the carbon-holders so that the carbons project only their points, 
 
32 
 
 but, as they burn away, the springs behind the carbons push them 
 forward, just as a candle in a carriage-lamp feeds up. 
 
 Abutment feeding is not new ; it has been applied to the 
 negative carbon before now, but not before to both carbons. 
 
 One great difficulty in the use of the Electric Arc light in 
 lanterns has been the impossibility of obtaining at a reasonable 
 cost a lamp which would give a steady light without constant 
 attention. Hand-fed lamps requiring adjustment every two or 
 three minutes were found to be a great inconvenience, while a 
 really good automatic lamp not only cost £15, but required a 
 special lantern of large size for use with it. 
 
 In the Newtonian lamp, Major Holden, R.A., has designed a 
 lamp which is self-feeding and focus-keeping, and which yet 
 dispenses with coils, magnets, and all similar complications, and 
 depends entirely on simple mechanical arrangements which can 
 be readily understood and managed by any lanternist. 
 
 The lamp works well either from dynamos or accumulators, 
 and is made to clamp on the rod of the tray of any ordinary 
 lime-light lantern. In the Fig. 28 it is shown clamped on the rod 
 of one of the adjusting trays. 
 
 Fig. 28, Pattern A. 
 
 In cases where the electric current is not laid on, it may be 
 obtained from accumulators, which can be charged as often as 
 necessary. The following particulars may be useful : — 
 
 Thirty-four portable cells in wood boxes, with lids, will give a 
 current of nine amperes at 65 volts, for three hours. Each cell 
 
33 
 
 I 
 
 measures 3^- inches x inches x 13 J inches over all. 
 weight about 5 cwts. Price .£27 14s. 
 
 Voltage and Current. — Either of the lamps, pattern 
 B, can be used wherever there is 
 a supply of electric current (direct, 
 or alternating) available, the re- 
 quirements being not less than 60 
 volts and a current between 4 and 
 10 amperes; under 4 amperes the 
 light is insufficient for ordinary 
 lantern purposes, and above 10 
 amperes the heat evolved is too 
 great for lanterns not specially con- 
 structed ; about 8 amperes is de- 
 sirable for most purposes. 
 
 Added Resistance in Circuit. 
 
 — A resistance varying with the 
 voltages of the supply and the 
 current used in the lamp must be 
 included in the circuit with the 
 lamp, the proper amount being 
 shown in the table of resistances. 
 
 Total 
 A and 
 
 Fi°\ 29, Pattern B. 
 
 IRON WIRE. 
 
 Table of Resistance for Various Voltages and Currents. 
 
 Current 
 
 amperes. 
 
 Resistance in ohms for Volts. 
 
 Iron Wire 
 of suitable size. 
 
 Feet 
 
 per 
 
 ohm. 
 
 60 
 
 65 
 
 70 
 
 80 
 
 90 
 
 100 
 
 110 
 
 4 
 
 4 
 
 5 
 
 6-2 
 
 87 
 
 11 
 
 14 
 
 16 
 
 035 No. 20 BWG 
 
 18 
 
 5 
 
 3 
 
 4 
 
 55 
 
 7-0 
 
 9 
 
 11 
 
 13 
 
 •619 No. 18 B WG 
 
 30 
 
 6 
 
 2-5 
 
 35 
 
 4*5 
 
 60 
 
 75 
 
 9 
 
 11 
 
 )) 
 
 >> 
 
 7 
 
 2 
 
 3 
 
 4 
 
 5-0 
 
 65 
 
 8 
 
 9 
 
 
 >» 
 
 8 
 
 1*9 
 
 25 
 
 35 
 
 4 5 
 
 55 
 
 7 
 
 8 
 
 065 No. 16 BWG 
 
 60 
 
 9 
 
 17 
 
 22 
 
 27 
 
 4-0 
 
 5*0 
 
 6 
 
 7 
 
 5 5 
 
 )} 
 
 10 
 
 1*5 
 
 2 
 
 25 
 
 35 
 
 4-5 
 
 5*5 
 
 6*5 
 
 ?5 
 
 y y 
 
 11 
 
 1-3 
 
 1-8 
 
 23 
 
 3 2 
 
 4 1 
 
 50 
 
 5*9 
 
 •083 No. 14 BWG 
 
 95 
 
 12 
 
 1-2 
 
 1*7 
 
 21 
 
 2 9 
 
 37 
 
 4-6 
 
 54 
 
 y y 
 
 y y 
 
 13 
 
 1-2 
 
 1-5 
 
 1-9 
 
 27 
 
 35 
 
 4 2 
 
 50 
 
 yy 
 
 yy 
 
 14 
 
 11 
 
 1-4 
 
 1*8 
 
 25 
 
 3*2 
 
 4-0 
 
 46 
 
 yy 
 
 
 15 
 
 10 
 
 1-3 
 
 1*6 
 
 2 3 
 
 30 
 
 3 6 
 
 4 3 
 
 yy 
 
 iy 
 
 The cost of the above resistances in a simple portable form is 
 from 15s. to 45s., according to the current. 
 
 c 
 
34 
 
 Diagram of connections, Fig. 27, for 8-ampere A pattern 
 Newtonian Lamp on 65 volt circuit. 
 
 Diagram of connections, Fig. 27, for 10-ampere B pattern 
 Newtonian Lamp on 100 volt circuit. 
 
 The makers put these lamps forward for continuous current 
 only, but they may equally as well be used with alternating cur- 
 rents. If both carbons are made the same in diameter they work 
 better with alternating current than when the negative is thinner 
 than the positive, as in the lamps usually made. 
 
 Messrs. Newton & Co., Fleet Street, make these lamps in 
 every required form and size. 
 
 THE KRUEGER ARC LAMP. 
 
 Fig. 30. — This lamp was designed and is specially adapted 
 for use in theatres, halls and public buildings, and is claimed to 
 be the best means for obtaining brilliant lighting effects for stage 
 work. It takes the place of the calcium light, and is stated to be 
 superior to it in many respects, as it is easy of transport, and far 
 more economical. 
 
 In the accompanying illustration the lamp is shown attached 
 to its supporting stand, equipped with a silvered parabolic re- 
 flector ; but the lamp is so arranged that the reflector can be 
 quickly and easily removed, and a lens box or Olivette box 
 substituted for it, making it possible to use a single lamp for 
 varied effects. 
 
35 
 
 The illuminating power of the lamp is said to be 3,000 
 candles, and owing to the simple but ingenious mechanism, the 
 light is maintained very constant. The lamp is practically 
 noiseless in its operation, and owing to the entire absence of any 
 devices depending upon gravitation in the regulating mechanism, 
 it can be inclined to any desired angle without interfering with 
 its operation, and without any re-adjustment. 
 
 In operating the lamp, connection can be made direct to the 
 supply wires of a 110-volt constant potential lighting system, 
 observing that the current passes in the right direction through 
 the carbons, and under these conditions the rheostat in the 
 perforated cone at the base of the lamp will reduce the current 
 passing through the lamp to the proper strength. 
 
 The lens box is used when it is desired to concentrate the 
 rays of light more or less according to adjustment. It is very 
 useful in cases where it is desired to throw a strong beam of light 
 upon a moderate-sized object upon the stage, or to follow an 
 object in its movements. 
 
 The Olivette box is used when a uniform dispersion of light 
 over a considerable area is desired, which result is secured by 
 means of a ground glass front. In front of the ground glass a 
 colour frame is provided, open at both sides, so that frames can 
 be slid through in succession, and the colours changed without 
 showing the white light. 
 
 The Krueger lamp is manufactured by the Western Electric 
 Company, of Coleman Street, E.C. 
 
 PILSEN-JOEL AKC LAMP. 
 
 The lamp, Fig. 31, is one of the P 13 type — a stand lamp — 
 and is fitted on the adjustable camera stand, and designed and used 
 in many installations for printing photographs and reproducing 
 photo-engravings, and such work, and gives a nominal 6,000 
 candle-power. The light is reflected with increased power on 
 any special object. The reflector is adjustable in any direction, 
 and the lamp, with reflector only, without the stand, is useful 
 as a search lamp or cargo lamp, and for signalling and other 
 useful purposes. The light is exceptionally steady and reliable ; 
 the Pilsen lamp is, as is well known, very simple in construction, 
 being self -regulating by the electric current only, and has no 
 clockwork or tooth-wheel gearing, and is easily manipulated and 
 kept in working order by any intelligent workman. 
 
 c 2 
 
36 
 
 Ordinary arc-lamps, such as are used in lighting, can be used 
 for photo-printing, and are much used for that purpose, although 
 they are by no means well adapted to it. 
 
 Any make of lamp for 20 or 25 amperes will serve this 
 purpose, two of them being used in series, and the light from each 
 lamp thrown on the print from opposite sides. 
 
 Fig. 32 represents a focussing Crompton Pochin lamp, which 
 is as good as any other for the purpose, and which are now cheap. 
 They work well with alternating current. In adopting ordinary 
 lamps for photo purposes, one must see that he gets a lamp for 
 alternating currents if he is in an alternating current district. 
 
37 
 
 Many lamps go equally well on any circuit. Among these are 
 the Crompton, Brush, Brockie-Pell, Kennedy, and Lewis lamps. 
 It is only necessary in ordering to state the kind of current 
 supplied and the frequency. 
 
 Fig. 33. 
 
 Fig. 33 is a Kennedy hanging arc-lamp. To adopt it for 
 printing purposes a conical reflector is fitted as in Fig. 3i. This 
 
38 
 
 reflector is about 20 inches diameter and six or eight inches deep, 
 of common iron, and kept brilliantly white inside with pure white- 
 wash made of clean whitening and clean water, into which clean 
 isinglass is added to make it adherent. 
 
 The reflector is hung usually by an iron strip, bolted to the 
 frame of the lamp. 
 
 A focussing lamp is almost necessary 
 in every case for this purpose. 
 
 The reflector is slotted out so as to 
 clear the lamp rods. 
 
 For photo printing, on a large scale, 
 the ordinary lamp so fitted is very waste- 
 ful, and a better arrangement is shown 
 at Fig. 35. Here a large hood, made of 
 sheet iron or zinc, is fixed to a deal bench 
 for printing over a surface of 5 x 3 feet. 
 The hood is made 5 ft. x 2 ft. 6 in., and 
 three arc-lamps are placed inside, prefer- 
 ably of the Fig. 1 1 type ; or any other good 
 lamp which stands upright may be used. The 
 author’s Fig, 1 1 type is cheap and handy. 
 
 With three lamps, of 20 amperes each, 
 and with the hood brilliantly whitewashed, 
 an engineer’s or architect’s tracings can be 
 copied on blue prints in 15 minutes, with 
 four lamps in 10 minutes ; ordinary photo- 
 graphic negatives in the same time. 
 

 39 
 
 This is a simple apparatus, and can be built by any car- 
 penter and tinsmith. It 
 can be made very power- 
 ful, for into this hood five 
 lamps of 20 amperes can be 
 placed. 
 
 A still better arrange- 
 ment is to use horizontal 
 lamps in a conical reflector. 
 And as this arrangement 
 is good for either copying 
 or printing and is the 
 simplest arrangement, we 
 will describe it at length. 
 
 Fig. 36 shows the ap- 
 a conical reflector for one 
 arc light. It may be hung or it may be on a stand, so that it can 
 swivel in any direction. 
 
 The reflector is pure white inside and about two feet in 
 diameter. 
 
 It is built on the Pilsen principle and is suitable for continuous 
 
 Fig. 36. 
 
 pearance of a horizontal lamp with 
 
40 
 
 current working. The tube carries a double-coned core, F, 
 working through two coils, S 1 and S 2 ; the tube is guided by two 
 pulleys at its outer end, and by two smaller pulleys between the 
 coils ; a dash pot is formed of the lower end of the heavy wire 
 coil, S 1 . The reflector is fixed as shown. 
 
 Finding no very satisfactory horizontal lamps in the market, 
 the author made some experiments in the hope of discovering a 
 simpler and better arrangement, and with a view of making a 
 
 Fig. 38. 
 
 lamp equally suitable for any circuits, continuous or alternating, 
 Fig. 38 is the result, and shows the construction diagrammatically. 
 
 It has only one coil, a shunt coil, and the arc is fed by 
 this coil in opposition to a weight, which weight can be 
 adjusted to a nicety by adding or withdrawing shot. The weight 
 hangs on a cord over a pulley, which also acts as a guide-pulley. 
 
 The clutch, E, grips the rod, A, when no current is passing, 
 and the weight draws the carbons apart, carrying the clutch on 
 the rod; but when current is turned on, the iron core, D, is 
 pulled down, and the lever, G, pushes back the clutch and rod until 
 the carbons meet, the weight then overpowers the coil, and the 
 carbons part to form the arc. As the carbons burn away 
 the coil gets stronger, and pulls down the lever, releasing the clutch 
 and allowing the lamp to feed. 
 
 Coil C is of fine wire; for continuous currents 2 lbs. of 
 No. 30 B.W.G. 
 
41 
 
 For alternating currents it is wound to suit the frequency, 
 Nos. 26, 24, 22, B.W.G. wire being used for 83, 100 and 133 
 frequency. The core is f-in. laminated iron, the bobbin is 
 made of vulcanised fibre, and is 4 in. long, 3 in. outside diameter 
 of flanges. The core should not be less than 6 in. long. 
 
 Fig. 39 shows this lamp used in a large conical reflector, or, 
 rather a hopper-shaped reflector. Four lamps are shown, in one 
 
 reflector, 5 ft. x 3 ft. at the open end. Such an apparatus is 
 most effective; all the light is utilised, and a surface of 5 ft. x 3 ft. 
 can be printed in a few minutes, with 20 ampere currents in 
 each lamp. 
 
 We have hitherto considered only one lamp and reflector for 
 portraiture work, namely, the hand-fed lamp (Fig. 10). The 
 lamps described are principally useful for printing, copying, 
 enlarging, &c. 
 
 AUTOMATIC PORTRAITURE LAMPS. 
 
 We now come to the consideration of Automatic Photo- 
 Electric Lamps for studios. 
 
 We will consider the simplest and cheapest forms first. 
 
 About 12 years ago a good deal of interest was excited by 
 the introduction of an arc-lamp known as the “ Sun” lamp, or 
 lampe soleil. In it the arc is formed across the face of a small 
 block of marble. The surface of the marble becomes incan- 
 descent, and as the arc clings to it a remarkably steady, soft light 
 is produced, much like good sunlight. The carbons do not burn 
 away quickly, and the marble lasts from 12 to 20 hours, and is 
 easily renewed. This electric lamp has been applied to photo- 
 
42 
 
 graphic purposes by Mr. Boordman in a lamp made by Messrs. 
 N alder & Harrison, in the form suitable for portraiture shown in 
 Fig. 40. The block of marble is held on the circular dish in the 
 
 centre, and the two carbon 
 rods enter, one from each 
 side. The whole thing is 
 small, compact and exceed- 
 ingly simple, requiring no 
 moving mechanism. 
 
 The marble, besides 
 acting as a path for the 
 arc, also acts as a reflector 
 and throws the light up 
 into an umbrella-shaped 
 reflector of large size, as 
 shown in the figure. 
 
 The whole arrange- 
 ment is carried on a light 
 stand as shown. 
 
 This is a somewhat 
 primitive arrangement, but 
 the makers can hang it on 
 swivelling gear or on a 
 rising and falling stand, 
 and thus meet the requirements of photographers. 
 
 The important point in this apparatus is the lamp, which is 
 simplicity itself and produces a powerful photographic light with 
 any kind of current, alternating or continuous ; and one point in 
 its favour is its noiselessness under all circumstances. 
 
 It takes a good deal of current for the light produced, but 
 that may be compensated by its simplicity and the good light it 
 produces. 
 
 A better arrangement than the one shown is to have the 
 electric lamp fixed in the reflector, so that both may be moved 
 together when directing the light on a sitter, and a conical 
 reflector would be an improvement. 
 
 The next arrangement for portraiture is one of the author’s 
 design, and is made for any kind of current. It is a clutch lamp, 
 and is shown in diagram in Fig. 41. A single coil works a 
 laminated core, which pulls up a clutch lifting the sliding rod 
 and so forms the arc ; as the arc lengthens the current 
 
 Fig. 40. 
 
43 
 
 decreases and allows the rod to slide forward by the coil 
 dropping the core and clutch. Fig. 42 is the general arrange- 
 ment ; at S is a universal joint and at S 1 another universal 
 
 S 
 
 s 
 
 Pig. 42. 
 
 joint, so that the whole thing may be turned in any direction 
 whatever, and it works with either kind of current. 
 
 The mechanism of the Planet lamp, before described and 
 illustrated in Fig. 26, would make an excellent feed mechanism for 
 these large portraiture lamps, but the most desirable mechanism 
 
 Pig. 41. 
 S' 
 
 a 
 
44 
 
 is one which will work on any current, and is therefore universally 
 applicable. 
 
 The old clutch mechanism of Weston’s lamp is an excellent 
 one when used with laminated magnets. 
 
 The Pilsen lamp has long been made by G wynne and Co. 
 for a portraiture lamp. Fig. 43 is a diagram of this lamp 
 
 mechanism. A double-coned core works through two coils of wire, 
 one a fine wire coil the other a thick wire coil ; the cone is back- 
 balanced by a sliding weight. When the lamp is properly wound 
 for the current it is intended to use with it, the weight and the 
 cone with all its attachments should just about balance each other. 
 If any difference exists it should be in favour of the core, but no 
 more than an ounce at most. 
 
 For continuous currents it makes a good mechanism for 
 feeding the carbons, and is simple to make. 
 
 It is also made for alternating current circuits, the cores 
 being laminated, and the special construction is patented for this 
 purpose. 
 
 The author’s apparatus, lamps, reflectors, and other electrical 
 machinery are presently made by the Phoenix Dynamo Manufac- 
 turing Company, Hubert Street, Bradford, Yorks. 
 
45 
 
 Fig. 44 is a view of the complete apparatus on a stand. 
 
 Another photographic portraiture 
 
 apparatus is made by 
 Adamson, of Glasgow. 
 In this apparatus the 
 lamps are incandescent 
 lamps, each of 50 candle- 
 power ; 40 of them are 
 used in each apparatus ; 
 they are arranged round 
 the mouth of a circular 
 umbrella- shaped reflec- 
 tor of thin silk stretched 
 on a frame. Fig. 45 
 illustrates the complete 
 apparatus on a swivel- 
 ing frame. This frame 
 is well designed for its 
 purpose, and is a model 
 of what a carrying swivel 
 overhead should be for 
 Photographic Lamps. 
 
46 
 
 Fig. 46 is a sectional view of the lamp reflector, and shows 
 the lamps on the outer circle. 
 
 The lamps are connected through an elaborate switching-box 
 by numerous wires for the purpose of 
 varying the power of the lights. 
 
 The author has seen excellent photos 
 taken by this apparatus, but as to its 
 working he has no experience, and there- 
 fore cannot give any further particulars 
 about it. 
 
 Another design by the author for a 
 portraiture apparatus employs JablochkofF 
 candles. Five of these can be used on a 
 200 volt circuit or on a transformer. 
 
 The five candles are stood in a row 
 on a slate or stoneware strip, as in Fig. 47. 
 A bent tube suspends the whole apparatus, 
 and the reflector is in this case simply a flat, square sheet of 
 smooth zinc, brass or steel, whitewashed. 
 
 A screen, in front of the candles, keeps off the direct light. 
 
 This is a simple and excellent apparatus with alternating 
 currents ; it will work perfectly and give a very powerful light. 
 In fact, by making the reflector about 6 feet x 3 feet 6 inches, 
 a large group, such as would fill a theatre stage, may be taken 
 at once. 
 
 With continuous currents it requires to be worked inter- 
 mittently, for the current has to be reversed every five minutes ; 
 
47 
 
 but that is no great drawback, as an exposure only occupies a few 
 seconds. 
 
 The same apparatus, Fig. 55, is designed by the author for 
 photography by means of incandescent gas lamps, commonly 
 known as Welsbach burners. 
 
 We may consider another design by the author for an 
 Automatic Photo-Electric Lamp. It is another form of clutch 
 
 C is a clutch of which a large size diagram is shown in 
 Fig. 49. By the tilting up of the clutch, when the coil, M, is 
 
 IIIIIIHIIIIIll 
 
 Fig. 49. 
 
 energized by the current, the carbon-holder rod is gripped and 
 lifted up to form the arc. When the arc burns wide, the coil Q, 
 
48 
 
 a shunt coil, pulls the lever down and so releases the clutch to 
 allow the rod to slide through and thus maintain the arc. 
 
 Arc-lamp makers will see readily that almost any of the well- 
 known arc-lamp mechanisms will feed a Photo-Electric Lamp, 
 provided always that there is no gravity action in the feed. If 
 there is any gravity action required, it may be on the moving 
 carbon-holder, but never in the feeding mechanism of the lamp. 
 
 For instance, in Fig. 41 we have a core (C) in the mechanism, 
 which acts by gravity. This is a drawback to that mechanism, 
 for it requires the lamp to be used always at the same angle, so 
 that gravity may always be the same. This is not of much con- 
 sequence, however, for there is only one angle at which the best 
 portraiture work can be effected — an angle of about 45. 
 
 In the mechanism of Fig. 48 only the upper carbon-holder is 
 affected by gravity, and that is compensated by a sliding weight 
 (W) working over a pulley by a cord. 
 
 Another point in this mechanism is the use of a spring instead 
 of the shunt coil. A spiral spring does equally well, and renders 
 the lamp cheaper and more suitable for alternating currents. 
 
 In some arc-lamps two pairs of carbons are burned simul- 
 taneously, and by that means the same light is obtained with half 
 the current used ; thus, two 25 ampere arcs are equal to one 
 50 ampere arc, and as the same pressure is supplied to work the 
 two 25 ampere arcs as that supplied for the one 50 ampere arc, the 
 electricity consumed in one case is 25 x 110 = 2,750 Watts ; in 
 the other is 50 x 110 = 5,500 Watts — just double. 
 
 Double lamps will not work well on 100 volts pressure. They 
 require over 105, and work best at 110 volts. The reason is 
 that considerable resistance is always required in a lamp circuit 
 to enable the lamp to feed, and if sufficient resistance is put in to 
 steady the lamp feeding, it reduces the current too much ; thus, 
 on 100 volt circuit, two 45 volt arcs = 90 volts, leaving only 
 10 volts of a surplus, and 10 volts divided by 25 amperes 
 = ia = 0*4 ohms, the resistance which could be used — a 
 resistance too small for steady work; but with 110 volts we 
 have a surplus of 30 volts, which, divided by 25 = =1*2 
 
 ohms resistance, which may be inserted, and this will be found 
 to give a good result with two arcs in series of 25 amperes each. 
 
 Double arc lamps with hand-feeding work well, down to 
 100 volts. If the operator takes a little pains to learn the art of 
 hand-feeding, it is easily acquired, and is a perfect feed if one 
 
49 
 
 only takes the little necessary trouble. Any of the lamps 
 described can be made double arcs by several devices ; some 
 devices for double arcs are, however, patented, and therefore 
 cannot be supplied by every firm. 
 
 Gwynne and Co., as already stated, have a patented device 
 for making their Pilsen lamp a double arc, and it answers well. 
 
 Fig. 50. 
 
 Fig. 50 A is another ■ portraiture-lamp by Borland, of 
 Leeds. The lamp mechanism is that shown in Fig. 25, the 
 scissors lamp. The reflector is four feet in diameter, and curved 
 into a sort of parabolic form, called an umbrella reflector. 
 
 COPYING LAMPS. 
 
 Fig. 51 is the usual arrangement for copying. The lamp 
 best for this purpose is that described in Figs. 19 and 20. 
 
 D 
 
50 
 
 The picture to be copied is pinned against a board upright 
 on a suspended pair of rails. The camera is carried on a sliding 
 table on the same pair of rails, the lamp is hung to one side 
 sufficient to clear the view of the camera, and the light is thrown 
 on the picture obliquely. If the picture has a glazed surface, care 
 is taken that the reflector from the surface, acting as a mirror, 
 does not fall upon the camera lens. This can be avoided by 
 adjusting the angle of incidence of the light from the lamp. 
 
 Two lamps may be used, or three — one on each side and one 
 above — if the picture is large. 
 
 Fig. 52 is a diagram showing how the apparatus shown in 
 Figs. 38 and 39 is used for printing from negatives or tracings. 
 
 It has four lamps in a reflector ; in front stands the frame 
 with the matter to be printed. 
 
 Four lamps of 15 amperes do this work well. 
 
 This apparatus costs .£25 — that is, the four lamps and the 
 reflector, with a resistance and switch. 
 
 The horizontal lamps for copying are sold complete for £10 
 each, with proper conical reflector fitted. 
 
 As to the prices of complete sets of photo-electric plants, of 
 course, different makers put different values on the same products, 
 
51 
 
 and the price-lists are not always a safe guide to go by. As the 
 author has considerable experience in the making of electrical 
 machinery and apparatus, he ventures to estimate the fair price 
 for photo-electric sets, including variable resistances with switch, 
 an ammeter and suspension gear, reflectors, lamp, and all 
 complete, to work up to 70 amperes at £25 nett, if automatic; 
 double arc set same price. No difference, whether alternating or 
 continuous. This price does not include any fixing, painting, 
 packing, discount, carriage, wiring or starting up, or any extras 
 whatever. 
 
 For a hand-fed set with reflectors, lamp, suspension gear, 
 resistances, switch and ammeter, .£15 nett, same terms as above. 
 
 These, of course, are the author’s prices. Other designers 
 may be able to make cheaper designs, and others again will be 
 found to be dearer, but these figures may be taken as a fair 
 average estimate, allowing for good workmanship and materials 
 and good working designs. 
 
 For printing photographic negatives, a very effective ap- 
 paratus, worked by the author, is shown in Fig. 53. A 50-amp^re 
 
 arc-lamp is required, preferably a focussing lamp, as shown. 
 This is hung in a large, conical reflector, F F, with a dead-white 
 surface, and to this is fixed an inverted conical reflector, S, upon 
 which to lay the negatives, as shown at P P. The opening at the 
 
 d 2 
 
52 
 
 top of the reflector should be 18 inches diameter, and the 
 diameter at the widest part 4 feet. The opening at the bottom 
 should be 2 feet diameter. 
 
 With this apparatus, prints may be made in ten to twenty 
 minutes of fairly dense negatives. 
 
 The apparatus is suspended by a hook, as shown. The 
 reflector is shown in section ; it is circular in shape, and made of 
 tinned iron. 
 
 With all these apparatus for providing him with effective 
 artificial light for his work in every line of business, the photo- 
 grapher is now independent of seasons and weathers. Hitherto 
 the plant has been too expensive for general adoption ; but it 
 will be gathered, from this brief description of the various 
 apparatus, that cheap and effective lamps and appliances are or 
 will be available. 
 
 For optical work, or for enlarging photographs, the arrange- 
 ment shown in Fig. 54 may be used. The lamp shown is the 
 “ Scissors ” lamp of Borland, Leeds, but another form may be 
 used if desired. It is essential that the arc be fixed in the focus 
 of a condensing lens, C, to make the rays parallel in passing 
 through the picture. An ordinary magic lantern condenser is 
 first-rate for this purpose. 
 
 The figure shows the general arrangement. The front is 
 simply a magic lantern front, with photo object-lenses, and a large 
 condenser, 5 or 6 inches diameter. The current required is 10 
 to 15 amperes. 
 
 GAS PHOTO APPARATUS. 
 
 Every photographer is within reach of a gas supply, so that 
 this apparatus is available where no electric supply is to be had. 
 
 The author’s apparatus consists of a white-washed reflector 
 of sheet zinc, hung in a frame of |-inch iron piping or ^-inch 
 
53 
 
 
 rod iron. The reflector may be made large, but the smallest size 
 of any use is 3 feet 6 inches square. For this size 10 burners 
 may be used, each placed as close to the other as they can be 
 fixed. A 4 ft. 6 in. reflector should have 16 burners. 
 
 It is not necessary to screen off the direct light of the burners 
 except very slightly, by either having the tubes ground on one side 
 or painted with alum water, or otherwise rendered semi-opaque. 
 
 Fig. 55 is a complete view of Kennedy’s Gas Photo-Electric 
 Apparatus ; W are the burners, F the reflector, and P a rubber 
 pipe to supply the gas. 
 
 Fig. 56 shows a tube for the burners half obscured on one 
 
 side. 
 
 The gas-light apparatus is cheap and handy, and can be 
 applied anywhere, and really makes beautiful work. The only 
 drawback is the heat and foul gases it gives off, but these can be 
 easily got rid of by a ventilator in the roof of a studio. 
 
 Fig. 57. 
 
54 
 
 ELECTRIC RE-TOUCHING. 
 
 Fig. 57 is an electric re-touching device, in which the pencil 
 is vibrated by a contact-breaker, the same as is used in induction 
 coils. It is driven by a pair of galvanic cells. 
 
 OPERATING THE RE TOUCHING DEVICE. 
 
 Attach the copper tips on the conducting cord to the brass 
 binding-posts of the battery. The two smaller tips attach to the 
 re-touching device. 
 
 Use whatever grade of leads that will best suit your touch. 
 
 To make a light stroke, turn the top adjusting screw to 
 the right. 
 
 To make a heavy stroke, turn it to the left. 
 
 The other adjusting screw must be left as it is. 
 
 Occasionally give the small wheel near the pencil-point a 
 quarter turn. The pencil-point wears off at an angle, and 
 this will give a new cutting edge. In this way you can re- 
 touch for hours without removing the pencil. 
 
 For blending, move the device lightly and rapidly. 
 
 There is no style of work you cannot do with this re -touching 
 device. 
 
 The length of the pencil-point is very important to do fine 
 work, and must extend from 1| to 1 \ inches in length from the 
 pencil-holder. 
 
 , 
 
 RANKIN KENNEDY’S PHOTOGRAPHERS’ 
 ELECTRIC PENCIL. 
 
 Figure 58. 
 
 This pencil is used by photographers for dodging or re- 
 touching photographic negatives. 
 
 In re-touching the defective lines or spots on a negative, the 
 
55 
 
 stroke of the pencil requires in many cases, in fact, in almost 
 every case, to be minutely small, and therefore to obtain the 
 desired effect is a very slow process, as these small strokes have 
 to be made with great care. 
 
 Recently, an American firm introduced a pencil which is 
 rapidly revolved by a small electromotor, so that the point of the 
 pencil spins, and thereby is rubbed on to any spot by simply 
 moving the point gently over it in any desired direction, thus 
 doing away with the necessity for the tiresome confined motion 
 of the operator’s hand. 
 
 Another method and apparatus also recently introduced from 
 Germany consists in fixing the negative in a frame which is 
 vibrated rapidly by an electro-magnetic apparatus. 
 
 The appliance herein illustrated is a British production, and 
 in it the pencil-point is very rapidly vibrated through an ex- 
 ceedingly small stroke by a simple electro-magnetic contact- 
 breaker, so that the pencil has only to be guided by the operator 
 while the electro-magnet performs the necessary rubbing at an 
 exceedingly rapid rate — about 200 strokes per minute. 
 
 It is claimed that this form is simpler and less liable to 
 derangement than the rotating form. 
 
 A battery of two large Leclanche cells work this vibratory 
 pencil, and where a number are in use one contact-breaker can be 
 arranged to work them all. Referring to the figure, P is the 
 pencil pivoted at R in trunnions, 0 is an ebonite case carrying 
 a bobbin of fine wire, H, B is the contact-breaker platinum screw 
 point, A is the armature — a light piece of soft iron passing 
 through the coil, M is a piece of soft iron fixed outside of the 
 coil to which the armature is attracted. A spring, S, opposes the 
 attraction, and sends back the armature, which is fixed on the end 
 of the pencil. It will be readily seen that the pencil-point makes 
 a small motion compared with the play of the armature. 
 
 ON THE ARC AND CARBONS. 
 
 Carbons for arc-lamps should be of proper size to suit the 
 current, and the positive carbon should be fixed to top or bottom 
 holder according to the use for which the lamp is used. For copying, 
 printing and other purposes with a horizontal lamp the inner 
 carbon should be the positive, that is the one on the moving rod ; 
 
56 
 
 with the upright lamps, the upper carbon should be the positive 
 for lantern work or for printing and copying. 
 
 With the Photo-Electric Lamp the positive carbon should be 
 the fixed one in the small bowl in every case. 
 
 Alternating current lamps have no positive or negative ; both 
 carbons burn alike, and should therefore be of the same size, and 
 both should be cored carbons. 
 
 Hard carbons last longer but give less light than soft ones. 
 
 When an arc hisses the arc is too short, when it flames it is 
 too long, and flaming occurs also with too thin carbons ; sputtering 
 is due to bad carbons. 
 
 Cored carbons must be used with continuous current lamps 
 for the positive carbon. Good cored carbons are easily got, and 
 so are bad ones ; the worst fault in cored carbons is want of con- 
 tinuity in the core. The only guarantee of good carbon is to have 
 it from well-known makers such as Conradty, Siemens’, Lacombe, 
 or Carre. The following is a list of carbons giving the proper 
 sizes for different continuous currents. For alternating the 
 sizes should be the same for both, and both cored. The column 
 for the negative carbons will give the sizes for the alternating 
 lamps : — 
 
 Current 
 
 in 
 
 Amperes. 
 
 Positive 
 
 Cored 
 
 Diameter. 
 
 Negative 
 
 Solid 
 
 Diameter. 
 
 
 m/m 
 
 m/m 
 
 5 and 6 
 
 9 
 
 9 
 
 8 
 
 11 
 
 9 
 
 10 
 
 13 
 
 11 
 
 15 
 
 15 
 
 13 
 
 20 
 
 18 
 
 15 
 
 30 
 
 20 
 
 18 
 
 50 
 
 25 
 
 20 
 
 80 
 
 30 
 
 25 
 
 100 
 
 35 
 
 30 
 
 140 
 
 42 
 
 35 
 
 170 
 
 50 
 
 42 
 
 200 
 
 60 
 
 50 
 
 These sizes will give the best efficiency, but for the best 
 light a pair of carbons 10 per cent, less in diameter may be used. 
 
57 
 
 Without a special adjustment, which no lamp in the market 
 has attached to it, a lamp made for 25 or 50 amperes will not 
 burn well at any other current strength, unless it is a hand-fed 
 lamp, and even then the carbons must be made proportional. 
 
 If a lamp hisses, when supplied with the proper current, it 
 indicates something wrong with the thick wire coil ; if it flames 
 with the proper current, it indicates something wrong with the 
 shunt coil — always presuming that the lamp mechanism is right. 
 
 A lamp which feeds by jumps and jerks, occasionally silent, 
 and then hissing, is radically out of adjustment, and requires the 
 attention of an arc-lamp expert to decide on its treatment, or the 
 maker of it must be called upon to set matters right. 
 
 If photographers would go to the slight expense of calling in 
 the advice of an electrician when contracting for a photo-electric 
 plant, much trouble would often be averted, as then the plant 
 would be tested and accepted only when correct. 
 
 In working the arc-lamps for photo purposes, it must be 
 borne in mind that mere brightness of light is no criterion of its 
 photographic power. The photographic rays are not the bright 
 light rays in the spectrum. It is a great mistake to put greater 
 than 50 amperes in an arc for photo-portraiture purposes. If a 
 large group is to be illuminated, two apparatuses, side by side, 
 should be used, each of 50 amperes. 
 
 A long arc, although giving less light than a short arc, is far 
 more powerful photographically ; so that a long arc, even although 
 slightly flaming, is the best for the purpose. A short arc can be 
 discovered by measuring the volts across the arc; if they are 
 under 42 or 43 it is short, if over 46 it is generally long and may 
 be as much as 50 volts. But different carbons alter these figures 
 somewhat, but not much. 
 
 As a general rule, the vertical inverted lamps, working as in 
 Fig. 15, are cheapest, and give less trouble than lamps working 
 at different angles. The lamps shown in Figs. 13 and 15 will 
 work at different angles, and for working on the separate lamp 
 and reflector system are perfect at the slight angles required 
 in that system. 
 
 It will be gathered, from this brief description of the various 
 lamps and methods, that the photographer has the choice of a 
 good variety. The umbrella reflector and diagonally-hung lamp 
 has served its purpose fairly well, but at best it is a clumsy and 
 unwieldy arrangement. 
 
The author’s experience points to the separate lamp and 
 screen system, or the inverted lamp with the diagonal flat 
 reflector, as the apparatus which, in the end, will be found much 
 preferable for Photo Portraiture work. 
 
 The General Electric Company’s Photo Lamp is a hand-fed 
 arrangement on a stand. The complete plant is priced £26. 
 
 The Lamp, Fig. 59, is arranged so that it can be directed 
 
 at will by the operator, so 
 as to give either a top, 
 side, or bottom light. It 
 is constructed so that the 
 sitter cannot get direct 
 rays, but only reflected 
 light. 
 
 The Reflector is 4 ft. 
 6 in. diameter, and made 
 of a light material, and 
 nicely balanced in the 
 stand. Internally it is of 
 a dead white, so that it 
 gives out a soft diffused 
 light. The stand is ad- 
 justable, so that it can be 
 raised or lowered to any 
 desired height. 
 
 The Light given is 
 10,000 candle power nomi- 
 nal, or, if desired, can be 
 varied either more or less 
 to suit requirements. 
 
 The shape of the re- 
 flector is correct in this 
 illustration, and generally 
 it is a useful plant. 
 
 It is a remarkable fact 
 that most of the public 
 supplies of continuous elec- 
 tric current are remark- 
 ably sensitive, and this ex- 
 traordinary weakness is 
 guarded against by Central 
 
59 
 
 Station Managers making strict rules regarding the use of 
 resistances in the circuit of large arc lamps for gradually turning 
 on the current. 
 
 Intending users of large arc lamps should therefore inquire 
 carefully as to these rules before arranging for them, for it is not 
 uncommonly the case that it would be cheaper to use a storage 
 battery, or to have an independent gas engine and dynamo, than 
 to comply with the said rules, which are not only absurd in most 
 cases but quite prohibitive of the use of arc lamps by photo- 
 graphers. 
 
 A day supply can in most places be got cheap— say, about 
 half the cost of the night supply of electricity. 
 
 Photographers ought to avail themselves of this fact by 
 storing their supply during the day load hours at the central 
 station. 
 
 By this means they not only get their electricity cheaper, 
 but also evade the stupid rules made by the managers to preserve 
 their sensitive balance. These remarks apply to continuous 
 current circuits. 
 
 On alternating current circuits there is no bother about 
 supplying large arcs. 
 
3^C'cl)' v ~=> 
 
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 C. MITCHELL, 
 
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 Fetter Lane, E.C. 
 
 
WILLIAMSON & JOSEPH, 
 
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 NEWTONIAN’’ ARC I. AMPS 
 
 For Optical Lanterns and Photography. 
 
 Self-Feeding. Focus-Keeping. Very Simple. Thoroughly 
 Efficient. 
 
 PATTERN “A,” £3 10s. Od. 
 
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 PROVISIONAL PATENT. 
 
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 LANTERNS, 
 
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 Optical Lanterns 
 
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 Price £4 4s. 
 
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 see Illustration, £5 10s. 
 
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 406 STRAND, 457 WEST STRAND. 7 GRACECHURCH STREET, 
 
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F. J. BORLAND’S 
 
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 PHOTOGRAPHIC APPARATUS 
 
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