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ilp archive : journals

public lighting no. 11 vol. 3: special conference number
September 1938


At Bournemouth: A Trail Of Brightness p59
Summary of of the lively debates and events at the Fifteenth Annaul Conference Of Public Lighting Engineers. The "Lambeth Walk" was particuarly enjoyed at the reception.
APLE: Conference


Bournemouth's 5-Year Programme p60
Capital expenditure for street lighting planned for Bournemouth over the next five years.
Lighting: Installations


The G.L.I.S. p60
The General Lighting Intelligence Service was instituted by Mr. H. L Juliusburger of Ladbroke Grove in 1937. It offers up-to-date information as to the development of the lighting world, both in the UK and places abroad. It has already produced eight issues. The statistics offer a useful form of comparison for lighting engineers, manufacturers and others interested in the actual production of street lighting systems.
Lighting: Publications


The Fifteenth Annual General Meeting p61
Notes taken at the meeting which was held at the Town Hall, Bournemouth on Monday 5th September 1938.
  • The membership was increasing at about a rate of one per week.
  • The Annual Report was appraised but members had to send in accurate figures if it was to be of real value.
  • Special mention was given to Mr. Wilkie for the Education Scheme and Mr. Lennox for calculating costs if the MOT Report was adopted. (The latter included the collation of thousands of figures, and a huge schedule had be prepared relating to 30 cases, which had been sent to the MOT).
  • The Minister had suggested that any lamp columns erected on trunk roads should have the approval of the Fine Arts Commision before the Ministry would pay a grant. Therefore all "steel and concrete people" had been approached by the APLE for drawings and these were put to the Fine Arts Commission that month.
  • The association was 180 in credit, with a balance sheet of 687.
  • The first lighting scheme under the Trunk Roads Act 1936 would shortly be installed after negotiations between Earley Parish Council, Berkshire County Council and the MOT. Sodium lighting was chosen which would cover a mile of the London Road through Earley to the outskirts of Reading. It would consist of Philora sodium lamps in ELECO GoldenRay fittings. The opening ceremony on October 17th was going to be attended by a large gathering of representatives of the highway authorities and various Associations concerned with lighting, road transport and road safety. It marked the first direct financial assistance by the Government towards securing greater road safety through trunk road lighting.
APLE: Organisation, Lighting: Design, Lighting: Installations


Opening Of Exhibition p62
Brief details of the opening of the exhibition.
APLE: Conference


The Presidential Address p63
Summary of the The Presidential Address.
APLE: Conference, Lighting: Education, Lighting: Floodlighting, Lighting: History and Lighting: Specifications


The M.O.T. Final Report p64
Summary and discussion of The MOT Report.
Points raised during the discussion: The tendency in the future would be to increase both height and spacing eg. 35' and 250'-300', there were too many posts for lighting dual carriageways, in every sharp bends a catenary system could be used; a committee of the British Standards Institution was now dealing with a standard specification for street lighting which would shortly be published, there were too many posts for lighting dual carriageways which was not good for economy or aesthetics, the MOT Report was of little use unless new administration of public lighting was introduced into the legislation i.e. it was 0.3d of the for rates in large cities, 3d. in the for small towns and and 1s in the for remote districts, street lighting should be part of ordinary highway costs, it would cost 3 million - 5 million per annum to carry out the recommendations in the Report and this was beyond local authorities - this money could be obtained if account were taken of the cost of accidents and there was a tax of 5s. per annum of bicycles; many towns owned their gas or electricity undertakings, but many did not want to spend money, and stated that the MOT Report was not mandatory but was a recommendation and so did not follow it; the MOT Report was not a yard-stick with which to measure the excellence of street lighting - this was good as the excellence of any installation was a matter of judgement, and the MOT Report indicated the general lines on how to obtain an efficient installation, the important thing was proper siting as then the equipment was given a proper chance; hours of lighting was not mentioned, except for dusk to dawn, and the lighting of different configuration of streets would be better achieved by light actuated controls; the lighting of double or S bends wasn't clearly specified as there should be overlapping of the lamps at the junction of the two bends; the Departmental Committee didn't contain any member who bought public lighting, although it contained many who made and sold equipment, the report dealt principally with main roads but 80% of the population lived in narrow roads, grants were only to be made for trunk roads and not other roads; illumination should not be measured but darkness, and greater attention should be given to the diversity factor, the tendency was of manufacturers to make miniture searchlights and to throw intense illumination on a given spot.
Reply: Mounting height of 25' primarily dictated by maintenance. The MOT Report in itself was a very good yard-stick. There should be overlap at the junction of two bends. The lighting of roundabouts required more attention. He hoped the MOT would provide more grants. As for diversity, if all the recommendations were carried out then there would be good uniformity of visibility.
Lighting: Specifications


List Of Exhibitors p66
List of exhibitors both inside the conference and outside on the roadway by the Exhibition Hall.
APLE: Conference


Air Raid Precautions And Lighting p67
Summary and discussion of Air Raid Precautions And Lighting.
Points raised during the discussion: The public could get accustomed to a state of continuous darkness, but switching lights off just before an air-raid might lead to lower morale; what was central control: was it the whole of an area administrated by one lighting authority or an area of supply?, regarding switching lamps during fog, unfortunately fog paid no attention to local boundaries; the real point of controversy is whether lighting should be extinguished upon receipt of a warning and brought into operation immediately after the raid, or whether throughout the period of hostilities all lighting other than specially arranged traffic signals should be eliminated; to extinguish all lights during an air raid would create more panic and chaos than would the actual falling of bombs; it was up to the manufacturers to devise a system of control of street lighting during air raids which would show up kerbs and generally permit pedestrians and traffic to move with a reasonable degree of saefy.
Lighting: ARP and Lighting: Control


The Bournemouth Gas And Water Company Entertain The APLE At Luncheon p69
Details of the luncheon and the speeches.
APLE: Conference


Public Lighting By Gas In Small Towns p73
Summary and discussion of Public Lighting By Gas In Small Towns.
Additional information was given about the lighting of Denton and lighting of Ormskirk, the MOT Report making lighting unaffordable for villages and small towns, and the instantaneous extinction of gas lighting lamps - it is possible to turn them off with a pressure wave control
Points raised during the discussion: Lighting authorities should get together and try to find some joint consultative means instead of consulting services, the gas industry was too prone to put in schemes which were just slightly more than the 3000 lumens per 100' linear (whilst electrical schemes were prone to use 5000 lumens), many local authorities did not light their areas, especially side streets, adequately, square lanterns could be used for the lighting of side streets if proper refracting and reflecting surfaces were used; gas industry had centralised control many years before it was applied to electrical methods; the whole of the street lighting in Berlin (gas and electric) was controlled according to the natural illumination prevailing and they were relying on total extinction during air raid periods, siting was far more important than lumen output; the paper should have expressed opinions of whether electricity was better than gas [he was reminded that this was not the function of the Association]; the consumption of by-passes was queried, the ARP requirements were also questioned (as one department suggested lamps to be used during an air raid whilst another department stated there would be no lighting); no consideration had been given to government finance to "service roads" along the main roads; the installation at Denton was the best low-pressure gas lighting system anywhere; cost was one of the biggest difficulties but not best use was made of the lamps now arranged; lighting was required after air raids as curiosity would bring a large number of people onto the streets, the pressure wave control system in Burton worked at 99% which surprised many engineers; for one local authority the penny rate brought in 30 and there were five miles of road to light and another brought in 50 for three miles - it was obvious that many local authorities could do nothing to improve their street lighting - the Home Office or Ministry Of Health should make grants - and 90% of the traffic which used those roads never paided a tax or rate in that district, the 7000 or 8000 lumens in the MOT Report was unncessary as 4000 lumens could do the job as well; could contracts made for 10 and 15 years be changed as progress was made, the average engineer and surveyor could do the job of a lighting engineer quite well for a small council; by-passes burned 6 to 8 cu. ft. per day, planning for ARP Lighting should be directed by the Home Office; one of the objects of the United Kingdom Gas Corporation was to provide a consulting service for small authorities especially as modern developments required specialised attention which small gas undertakings could not give; schemes were designed to deliver just over 3000 lumens per 100' linear as local authorities could not afford 5000-6000 lumens (either gas or electricity), side road lighting had been neglected and the MOT Report added to that neglect as it focused on main road lighting, lumens output was not criterion of efficiency and siting and positioning of lamps was more important, all gas contracts of 10 and 15 years were reviewed each 5 years.
Lighting: ARP, Lighting: Authority Organisation, Lighting: Control, Lighting: Funding, Lighting: Installations, Lighting: Luminaires and Lighting: Specifications


Conference Reflections p76
Summary of the Conference, the papers, events and hospitality. The papers themselves were summarised in this issue as there wasn't space to include them all; bound copies of the papers could be purchased from the Association.
APLE: Conference


Eastbourne And Evolution p77
Summary and discussion of The Development Of Street Lighting In A Country Borough.
Points raised during the discussion: The subject of gradation of light was poorly handled by the MOT Report and caused confusion, the lighting of bends was still problematical; comparing mercury and sodium lamps could be difficult as each had its advantages and disadvantages, it was an excess of candle power at the horizontal which was far more important than the intrinsic brightness of the source, therefore when comparing different light sources, the light distribution and mounting heights and planning should all be similar; a fixed policy for street lighting should be congratulated, it was necessary to light for motorists and pedestrians (which some discharge lighting enthusiasts ignored), the daylight appearance of fittings should be given more attention in industrial towns; a method for improving the power factor of low-pressure sodium lamps was suggested; glare was an important factor and should be considered, distribution was related to spacing and not to glare, the comparison between sodium and mercury was not fair as a scentific fitting was used for sodium whilst a decorative fitting was used for mercury; the lighting of open spaces was not considered; gradation in the MOT Report suggested that if a motorist moved from a well-lighting main street to a well-lighted road there should not be gradation, just because the MOT Report did not recommend something it should not be tried, comparisons of sodium and mercury had been carried out by questionnaire and the replies were honest, tests showed that 10% of light output was absorbed by dirty fittings and in Eastbourne the fittings were cleaned every six weeks.
Lighting: Colour, Lighting: Columns, Lighting: Control, Lighting: Environment, Lighting: History and Lighting: Installations


Technical Photography p83
Summary of the exhibit of technical photography by Hobbs, Offen and Co. Ltd
Lighting: Photography


Special Roots For Tubular Columns p84
Diagrams of the various special roots supplied by The Bromford Tube Company Limited for their tubular steel lamp columns.
Lighting: Columns


Radiation From Artificial Illuminants p87
Summary and discussion of The Radiation From Artificial Illuminants.
Points raised during the discussion: very power internally modulated lamps could be mounted at heights of half-a-mile or a mile high with only one or two lamps used to light a whole town; there was now very much less objection from the general public to the colour of the lighting when using electric discharge lamps, the main object of street lighting was visibility, the time was not far distant when much higher mounting heights and longer spacing would be possible and give the visibility required at a cost within the money available; had the pheonomena of luminescence been investigated as an option; internal moduled lamps were designed for different purposes and had very different lives from that required for street lighting, Telsa had attempted to light a city in the USA by means of poles hundreds of feet high with arc lamps.
Lighting: Lamps


The Annual Dinner p90
Details of the toasts, speeches, the King's telegram and formal addresses.
APLE: Conference


Progress In Electric Street Lighting p90
Ten years ago electricity was responsible for less than 40% of the total lighting of Britain's highways. Now it is 60%. The reason is that ten years ago the average cost of electricity for street lighting was nearly 2d. per unit - it is now 1.107d. per unit. Additionally due to the improvement of electric light sources, the 1d. can provide four to five times the light that could be obtained ten years previously. Furthermore the adoption of the MOT Report by many authorities has led to a 4000 hour lighting season (dusk-to-dawn all year) which results in comparatively little increase in cost with electricity and the relatively inexpensive maintenance of electric street lamps.
Lighting: Comparisons


Bath Road Lighting Scheme p90
Details of the Bath Road installation near Hayes which was the first installation in accordance with the MOT Report on that road.
Lighting: Installations


The Lighting Of The Frankfurt Streets Leading To The "Reichsautobahn" by Ernst Rothe, D.L.T.O. p91
A translation of an article from "Das Licht" published on the 10th March 1938. The building of the German Motor Roads, which was commenced on the 23rd September 1933, when the Fuehrer removed the first turf, prompted many towns to build a main entrance road to the "Reichsautobahn." About four years ago the town of Frankfurth-On-Main built the road for heavy traffic stretching from Frankfurth to Mainz and Wiesbaden when leads to the Reichsautobahn. The old lighting standards looked out of place - from both technical and architectural points of view. The lighting was effected by means of flat beam reflectors fitted with 150' lamps, the light source being 8 metres from ground level, the wooden poles spaced at 60 metres. The Frankfurt Town Council then decided to erect new lighting standards. Sodium vapour lamps were selected. A stretch of road 1.5km was built - it was 10 metres wide with, on either side, a green grass track, a row of poplar trees, a cycle track, a path for small carts and a footpath, so the total width is 65m - however only the heavy traffic part is lighted up. The lamps are 160W, 11,000 lumens output, mounted in the centre of the road, being 10m above ground level, and spaced at 44m. The distribution of light is effected by means of enamel reflectors 2x75° diffusion angle. The driver has 100 meters effective visibility. As it is the only lantern to use sodium light, the yellow colour serves the purpose of showing the people the way to the "Reichsautobahn" - other new roads use incandescent only to avoid confusion. Poles had to be 11.5m tall with a pull at the top of 300kg. The so-called "Stahlpanzermast" (Adastra Sectional Steel Poles) were selected - these poles had already been used in various towns in Germany.
Lighting: Colour, Lighting: Installations


A "Philora" Campaign p92
Philips have issued The "Philora" Plan For Public Lighting. Good public lighting is envisaged as embracing adequate intensity, reasonable uniformity, lack of glare, correct siting of units, correct contrast production, reasonable road brightness, low operating costs and easy maintenance. The booklet sets out the main recommendations of the MOT Report and features pictures of installations.
Lighting: Publications


Lighting For Pleasure Gardens p93
Description of scheme used for lighting the flower beds in the Pleasure Gardens, Bournemouth. It's a step-by-step guide on how to make the fittings.
Lighting: Luminaires


Illuminating Engineering Syllabus p94
A definite education scheme has emerged for the recognition by diploma of the status of Public Lighting Engineer. The scheme was the result of a meeting of a large number of associations, which had drawn up an advisory committee, and it included an Intermediate and Final Examination. The Final Examination was divided into Section A (general) and Section B (particular reference to Public Lighting). The regulations and syllabus were issued by the Department Of Technology at the City And Guilds of London Institute.

The Intermediate Examination will be of a standard which a candidate may normally be expected to reach after a course of part-time instruction over two years. The Final Examination will require an additional one to two years of study. Certificates of First or Second Class will be issued for all the examinations. All examinations will consist of a question paper of three hours duration.

Intermediate
1. Light Production And Control
Radiation from a hot body; the spectrum, visible and invisible.
Brief description of other forms of light production - luminescence, fluorescence and phosphorescence.
Electric discharge in gases.
Colour
Reflection (specular and diffused), refraction, transmission and absorption of light.
Simple polarised light.
2. The Eye And Vision
The eye; physiological optics; sensitivity to intensity and colour; persistence; adaptation; fatigue; glare; visibility and contrast.
3. Photometry
Measurement of light intensity from a point source.
Inverse square law and oblique incidence.
Photometers
Candle power, units and standards; mean spherical and hemispherical candle power; luminous flux and the lumen; candle power of sources with diferent colours; polar diagrams including Rousseau diagram and Russell angles; iso-candle diagrams; globe and other integrating photometers
Line and surface sources
The measurement of illumination; British and Metric units; the foot-candle and the lux; illumination photometers; iso-lux diagrams; brightness and its units.
4. Practical Light Sources
Daylight: qualities; admission into buildings; daylight factor and sill ratio.
Gas: the bunsen burner; various types of burner; high and low pressure fittings; the incandescent mantle; composition, properties and combustion of gases; products of combustion.
Lighting by acetylene, paraffin oils, petrol-air gas, oil gas.
Electricity: arc lamps; incandescent filament lamps, vacuum and gas filled; vapour discharge lamps.
Fittings: properties of glasswear; reflectors; refractors; diffusers; globes; shades and the effects on the amount and distribution of light.
5. Illumination
Effect of degree and nature of lighting in various situations; illumination required for various purposes; B.S. Specifications; rules for the avoidance of glare; shadow conditions; opportunities for general and local lighting; direct, indirect and semi-indirect lighting; reflection of light from walls and ceilings; application of fully diffused and uni-directional light; conditions of colour discrimination; study of lighting problems in houses, factories and streets; calculations necessary for spacing, height and positioning of lamps; aesthetic problems and architectural lighting.
6. Distribution And Control System
Gas: High and low pressure distribution systems; remote and automatic control apparatus.
Electricity: distribution systems; mains; switch-gear; protective apparatus.
Factors involved in costing; tariff schemes.
Final: Section A
1. Radiation And Light Production
Radiation: wave theory; quantum theory; line, band and absorption spectra.
Selective radiation and luminescence: fluorescence and phosphorescence.
Spectral energy curves: infra-red, visual and ultra-violet; spectral distribution from common light sources
Influence of spectra on coloured objects.
Photo-electricity.
2. The Eye And Vision
More advanced study of vision.
The retina; peripheral and foveal vision.
Sensitivity of the eye throughout the visible spectrum.
Vision at low intensities: dark adaptation; threshold measurements; Fechner's Law.
Colour vision by strong and weak light; the Purkinje effect.
Trichromatic theory of vision.
3. Photometry
Light standards and the full equipment of the photometric laboratory: screening; auxiliary apparatus; sector discs; rotators.
Special problems of heterochromatic photometery; the flicker photometer; yellow/blue ratio; use of colour filters
Physical photometers; their limitations and precautions in their use.
Final: Section B
1. Artificial Light Sources
More advanced study of light source and their equipment
Mechanical and thermal properties of glasses of various compositions
Optical properties of glasses and other reflecting media.
Use of refractors: symmetric and asymmetric refractors.
Design of projection apparatus; beam divergence, head lights, searchlights.
Further study of modern gas burners; high and low pressure.
Further study of electric lamps including vapour discharge lamps.
2. Lighting Installation
More advanced study of the planning of lighting installations.
Natural lighting; co-efficient of utilisation, room index.
Calculation of illumination due to point, line and surface sources.
Design for special applications e.g. streets, factories, workshops, schools, shops, offices, exteriors of buildings.
Influence of lighting requirements on architecture and building construction.
Organisation and adminstration of a lighting department.
Lighting: Education


Public Lighting Equipment p95
Brief description of the stands at the conference, and the display on the roadway outside the Exhibition Hall.
APLE: Conference


The "Wask" Raising And Lowering Gears p95
Brief description of a new brochure issued by Walter Slingsby And Company Limited
Lighting: Columns, Lighting: Publications


The "Radiovisor Light-Ray p95
Brief description of a new booklet issued by the Radiovisor Company.
Lighting: Control, Lighting: Publications


Lighting A New Zealand Street 90 Feet Wide p95
Details of the GEC scheme lighting a street 90 feet wide at Invercargill, New Zealand. The scheme treated the thoroughfare as two separate streets. The installation, incorporating more than 50 400W Osira lamps, has produced excellent results. Two sets of tramway rails mark the centre of the street. The lamps, housed in GEC Di-Fractor lanterns, are arranged in staggered formation in four rows down the length of the street; they are spaced 250' apart and the mounting height is 25'. The outside fittings are mounted on poles whilst the two middle rows are suspended on span-wires.
Lighting: Installations


Street Lighting Notes p96
Brief description of the installations at Bedford, Belfast, Bingley, Blackpool, Bridhouse, Burgess Hill, Calstock, Chatham, Chesterfield, Colwyn Bay, Dewsbury, Edinburgh, Finchley, Fleetwood, Gainsborough, Greenock, Guildford, Gunnislake, Hadleigh, Haslemere, Hebburn-On-Tyne, Hnely, Herne Bay, High Bentham, Ipswich, Kuntsford, Lanarkshire, Leatherhead, Lewisham, Leyland, Lincoln, Liverpool, Ludlow, Middleton, Midsomer Norton, Mirfield, Moffat, Nottingham, Oldham, Paignton, Pembroke Dock, Pickering, Poplar, Reading, Renfrewshire, Ripponden, Romford, St. Helens, Sherborne, Shipley, Slough, South Shields, Southwold, Stoke-Upon-Trent, Stratford, Tivertoon, Todmorden, Totnes, Troon, Walsall, Wanstead and Woodford, West Bromwhich, West Lothian, Worcester and York.
Lighting: Installations


Horizontal Burning Mercury Discharge Lamps in Lancashire p99
Description of a new installation in Stretford.
Lighting: Installations


Floodlighting At Bournemouth p99
Picture of the Hawthorns Hotel floodlighted with Primrose "Sieray" discharge lamps in Siemens fittings.
Lighting: Installations, Lighting: Floodlighting


Model Illustrating Correct Street Lighting p99
Description of the model produced by the GEC to illustrate the recommendations of the MOT Final Report. It consists of two parts - a realistic system of streets bounded by houses, cinemas and factories. The model measures 5' long by 2' wide, the lighting columns, road and spacing being to a scale of 1':380'. Running the whoel length of the model is a main arterial road - this is lighted by columns providing a mounting height of 25'. The two sections of the arterial road, which is divided by a roundabout, is over 40' wide: this is lit by a staggered arrangement of units not more than 150' apart, with an auxiliary unit centrally suspended every third position, so that there's no dark central section of the road. After the roundabout the road is made into a dual carriageway, the central reservation being over 6' broad. Dual carriageways must be treated as two separate roads, each having a staggered arrangement of lighting points with an average spacing of 150'. The fact that the central island is more than 6' broad necessitates the use of a column carrying two lanterns, each lantern being suspended over its own carriageway. Where the dual road bends away the lighting points become closer and on the outside of the bend only. Branching from the roundabout is another road which shortly divides into two, the major portion becoming an S bend. Round this bend the spacing becomes very close in accordance with the rule that says the angular separation between lighting points should not exceed a certain number of degrees. Other examples include lanterns that indicate to side road traffic that a main road is ahead; cross-road lighting with lights arranged just beyond the crossing; and roundabout lighting. The model was installed at Magnet House, London, and could be viewed there.
Lighting: Specifications, Lighting: Theory


Two New Devices For Use With Public Lighting Apparatus p101
Description of light-actuated control for gas lamps and an automatic cut-off for gas lighted bollards. Both were exhibited by Sugg at the Conference.
Light Actuated Control
Used for lighting street lamps between dusk and dawn. A recitified photo-electric caell is fixed in a suitable position on the lamp and is connected with the main control box. The components in the box include an electric relay, a 3-volt dry cell and a clockwork operated gas valve which incorportes a switching device. When daylight falls below a pre-determined value, the current from the photo-electric cell operates the relay, which allows a small current to flow from the dry-cell to energise an electro-magnet, which operates the trip mechanism on the clockwork gas valve, which then turns to the "on" position and lights the lamps. A similar operation occurs when the value of daylight increases to a pre-fixed value and the lamp is extingushed. It can be used for refuge islands with centre lamp; and for all lamps and signs on a roundabout. It is possible with Comet ignition to light all lamps up simultaneously. The only attention required is the winding of the clockwork mechanism - about once every three weeks - and the renewal of the battery - not more than once per year. The control was patented by Mr. W. H. B. Hall, Mr. R. H. Whillock and the South Metropolitan Gas Company originally for use in schools. It was developed by Sugg for street lighting in conjunction with the Public Lighting Section of The Gas Light & Coke Company.
Automatic Cut-Off Device
The possibility of an escape of gas igniting if a gas-illuminated bollard is knocked over was looked at by the Public Lighting Section of the The Gas Light & Coke Company. They devised an automatic cut-off valve which is being manufacturered by Sugg. The valve is fixed to the service in the base of the bollard, preferably below ground level, and the supply to the burner is conencted to it by means of an easily broken nipple, which ensures the valve not being broken away from the service if the bollard is knocked down. The device itself is diaphragm operated, the inlet gas passing to the underside of the diaphragm and thence through a valve to the burner. The effective area of the valve is small in relation to that of the diaphragm. Pressure at the burner is conveyed to the upper side of the diaphragm by a small bore tube, and under ordinary conditions, with almost equal pressure both above and below, the valve is kept open by its own weight. Immediate fracture of either the main supply or the small bore tube, the pressure above the diaphragm is reduced to atmospheric, and the inlet pressure snaps the valve shut and keeps it in this position until pressure is again applied above the diaphragm by means of reconnection. Owning to the success of this device, it is now being fitted to all gas lighted bollards and guardposts.
Lighting: Control


Adverts: British Commercial Gas Association, William Sugg And Co., Ltd., Walter Slingsby and Co., Ltd., Siemens Electric Lamps And Supplies Ltd., The British Thomson-Houston Co. Ltd., The Horstmann Gear Co., Ltd., Public Health Service Exhibition And Congress, British Electrical Development Association, Inc W Parkinson And Co., Engineering And Lighting Equipment Co. Ltd., Johnston Brothers (Contractors) Ltd., Bromford Tube Co. Ltd., Stewarts And Lloyds Co., Ltd., Gowshall Ltd., General Lighting Information Service, Radiovisor Parent Ltd., Metropolitan Vickers Electrical Co. Ltd, British Sangamo Company Ltd., Hobbs, Offen And Co. Ltd., Gas Meter Company, Foster And Pullen Ltd., REVO Electric Co., Ltd., James Keith And Blackman Co., Ltd. and The General Electric Co., Ltd.