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ilp archive : journals

public lighting no. 24 vol. 7
Jan-March 1942

Editorial p3
"What recommendation should I make to the Lighting Committee re estimates for the coming year?" This is a difficult question to answer. Their one desire is to keep everything under their charge at a 'ready to use' standard. However there is the Council to condend with. Some want to call a halt in spending on all public services which appear to be redundant. Seldom has public lighting forced its importance upon the public mind: Shops close at sundown; places of amusement restrict their hours; social activities are reduced to a minimum - all mainly because the streets are dark and unilluminated. More serious still is the toll of street accidents - mounting steadily month by month - not to mention the increase in crime reported daily by the police. If there is a public service that needs to be kept in order and ready for almost immediate use when called upon - it is public lighting. So the answer to the question is: "Recommend to your lighting committee that enough money is voted for public lighting to ensure that street lamps and all available equipment is kept in a state of readiness for that day when the present street lighting order is relaxed."
Lighting: ARP

News From Singapore p3
Message from Mr. Eric Evans, who now serves with the RAF in Singapore, and used to assist in the Secretary office at the APLE Conferences.
Lighting: Personnel

Fluorescent Lighting p3
The paper read by Mr. H. J. Jenkins before the Royal Society Of Arts was followed by keen interest by all those present. There were a large number of APLE members there. Would manufacturers develop fluorescent street lighting after the war?
Lighting: Lamps

Hands Off Those Columns p3
Certain newspapers have suggested that steel lamp columns should be "scrapped" for salvage. This must not be permitted. Every public lighting engineer knows the monetary value of his street light columns; he knows the costs of replacing them; and the number of months before they could be reinstated. The street lamp column should be left well alone by these well-meaning "salvage hunters".
Lighting: ARP, Lighting: Columns

A Layman's Point Of View by Mr. Eric Evans p4
Was employed with the Secretary of the APLE in the administration and secretarial side of the Association's activities. Now serving with the RAF in the Far East. Was in Capetown when experienced street lighting, without any restrictions, and how thrilling it was after "black out." Never before has the question of public lighting been placed so forcibly before the people. When the lighting is restored, I would imagine people's reactions would be of astonishment and great appreciativeness. He expects that some experimentation has been taking place so that post-war lighting will probably be even better. There is a patient enthusiasm being stored up in the minds of the publc, awaiting the day when lighting is restored. One of the most iterated remarks in England was "How nice it will be to have the street lights on again." This must be a great incentive to the APLE to keep together in readiness for the restoration of public lighting.
Lighting: ARP

Sgt. Pilot R. A. Eshelby, R.A.F.V.R p4
Ex-technical assistant in the "Philora" department of Philips Lamps, Ltd. is a prisoner of war. He was engaged in the Channel action against German battle cruisers.

Fluorescent Lighting (Extracts from a paper read before the Members Of The Royal Society Of Arts) p4
This paper was read by Mr. H. J. Jenkins, M.Sc., F.Inst.P., before the Royal Society Of Arts.
The property possessed by certain discharges of radiating relatively large proportions of their engenery in the visible part of the spectrum is well known. Thus efficiences of 50-70 lumens per watt are obtained from high-pressure mercury vapour and sodium vapour discharges. In the low-pressure mercury discharge, measurements show that more than half of the total energy in the positive column goes into powerful ultra violet lines of mercury at 2537A and below - the luminous efficiency of this discharge is only of the order of 5-10 lumens per watt. A considerable fraction of this UV energy can be converted into visible radiation by means of fluorescent materials, and since the light from the fluorescent materials can be controlled to a much greater degree than the discharge itself, it is possible to obtain light sources of greatly improved colour as well as of high efficiency.
Fluorescent Materials: The inorganic types include zinc sulphide, zinc cadmium sulphide and Willimite. The poweders are made luminescent by the addition of minute traces of heavy metals such as copper and manganese and subsequent furnacing at a high temperature. The effect of the heat treatment is to convert the amorphous powder into minute crystals, each of which becoms a tiny light source when irradiated with UV radiation of suitable wave-length. The first low-pressure fluorescent tubes to be made commerically were the high-voltage cold-cathode tubes developed by Claude-General Neon Lights Ltd. The early tubes used sulphide powers in conjunction with the mercury discharge, but since the powders were excited by long-wave UV, which was very weak in the discharge. there was little or no gain in effeciency. A considerable step forward was made by the introduction of zinc beryllium silicate, which can be developed in a variety of yellowish white and reddish fluorescent colours, and its efficiency is high. Magnesium tungstate was also used with red fluorescent substances. Two compounds which were developed some time later were cadmium chlorophosphate (discovered by the GEC at Wembley and resembles the red fluorescent variety of zinc beryllium silicate) and cadmium borate (discovered in the USA and gives a redder fluorescent colour than zinc beryllium silicate).
High-voltage Fluorescent Lighting: Reached perfection just before the war. The powders are not mixed together in a single tube, but each tube contains a single powder and the coloured light from the different fluorescent tubes is blended in the lighting unit. Attractive decorative effects could be obtained, and the mixed light have good colour rendering. The system has the further advantage that neon-filled fluorescent tubes can be used in addition to the mercury type, and enables a much larger range of white powders to be obtained than is possible in a single tube. The type of high-voltage fluorescent lighting unit standardised in this country comprises straight tubes about 9 ft. long and ¾ in diameter although other lengths of straight and curved tubing can be used. A typical unit comprises two outer tubes coated with zinc beryllium silicate and a centre tube coated with magnesium tunstate. The wattage is generally between 100 and 150W with efficiency between 20 and 30 l/W. A wide range of colours is available varying from warm pink or orange for recreational lighting to colours of the daylight type for commercial and industrial lighting. The units are run from leakage reactance transformers, one transformer operating from four to six tubes in series. The high open circuit voltage at the transformer starts the discharge instantaneously. Owning to limitations imposed by the cold cathode electrodes, the current through these tubes does not exceed about 60 mA. Thus the surface brightness is low, being only about ½ candles per cm2 for the brightest tube. This is a great advantage since no diffusing fitting is required to reduce glare.
The 5-Ft 80W Fluorescent Tube: In the years before the war, a range of wattages and sizes were under development in the UK and in America. Work in the UK was interrupted by the war, and then work was directed towards the production of a high-lumen-output type to meet the special needs of war-time industry. The choice of wattage and dimensions was largely decided by the desirability of utilising a choke already in production for HPMV discharge lamps.
Lumen Maintenance And Life: The light output falls off as the tube is burnt, due to the formation of desposits of metallic mercury and mercury compounds on the coating under the action of the discharge. The slow disintegration of the electrodes, part of which deposits on the walls, is also a contributory factor. The efficency of the 5-ft. tube falls to about 32 L/M in the first 100 hours, and to about 24 L/M after 2000 hours of life. The average efficiency throughout a life of 2000 hours is approximately 26 L/W. Manufacturers have not yet determined the ultimate life of the lamp, but the present objective figure is 2000 hours. The normal cause of failure is exhaustion of the electron emissive material on the cathode. A few hours before the tube finally fails, a 25-cycle flicker may develop due to current rectification or the discharge may flash with a lower or irregular frequency. These effcts are generally accompanied by considerable blackening in the region of the defective cathode, due to sputtering of the tungsten filament.
Effect of Mains Voltage Variation On The Characteristics: Overrunning a tungsten filament lamp improves the luminous efficiency, but impares the life, and underrunning has the reverse effect. With the 5-ft 80W fluorescent tube, overrunning reduces the efficency for reasons already discussed, and considerable underrunning will impair the life, since the discharge current is not then able to maintain the cathode at the correct temperature. Normal fluctuations of voltage which occur do not appreciably affect the performance of the tubes.
Operation On Direct Current: There are serious objects to operating fluorescent tubes on direct current owning to the need for a resistance to limit the current. The voltage drop of the resistance is generally of the same order as that across the tube and the wattage lost in the resistance is comparable with the tube wattage. The overall efficency may be reduced by 50%. A choke is necessary in addition to the resistance to provide a voltage kick to start the discharge.
By contentrating their efforts on a single type suitable for industrial lighting, British manufacturers have served the best interests of the country in the present circumstances. It seems unlikely that a range of wattages and colours will be manufactured in this country until after the war.
Lighting: ARP, Lighting: Lamps, Lighting: Lamp Auxiliaries

The Institution of Gas Engineers p6
The Report of the Chairman's Technical Committee contains a brief account of the membership and work of the Joint Lighting Committee. It states "There has been no change in the regulations relating to war-time street lighting. Gas street-lighting fittings complying with BS ARP/37, (referred to in "War-time Street Lighting By Gas" Publication No. 225), are being used for modified street-lighting installations throughout the country. Following experience gained with these lighting installations the Ministry Of Home Security, after consultation with the Committee, approved a special scheme for the lighting of gas works."
Lighting: ARP

Paper Shortage p6
Public Lighting is compelled to come into line with other publications and reduce its number of pages to comply with the Paper Restrictions Order. It is hoped that it will be possible to continue producing a quarterly issue. This has delayed the 1942 Annual Report.
Lighting: ARP, APLE: Journal

Fluorescent Lighting In Industry p7
Fluorescent lightign has been installed in the booking hall of Leicester Square Station where Stagg and Russell, Ltd., have a window display. The installation was planned by the Illuminating Engineering Department of Siemens Electric Lamps And Supplies,Ltd. and Sieray tubes were used. Owing to space limitations, it was necessary to design specially narrow trough fittings for fixing to the vertical glazing bars of the shop windows. The trough reflectors measure only 3½ ins. across. The old installation was 30 100W glas-filled lamps, running at 3kW, whilst the new installation has a loading of 1.25kW. The annual saving in electricity consumption is approximately 13,00 kWh, eqivalent to saving several tons of solid fuels. This point was brought home to the public by notices placed in each of the windows. The illumination of the windows is around 30fc while the old installation managed 15fc. The AC supply from the LPTB mains was at 33⅓ cycles, so special choke coils were required to give correct impedance. The windows are a constant source of atttraction and do not have to be "blacked out".
Lighting: ARP, Lighting: Lamps, Lighting: Installations

Lighting An Underground Aircraft Factory p7
Fluorescent lighting is used in a vast underground aircraft factory. A large number of Madza 80W 5' fluorescent tubes housed in Mazdalux fittings are being used to provide daylight lighting of high intenstity over the essential working areas.
Control units and condensers are accommodated on special straps in the suspension chains and the reflectors are of the open top type giving a reasonable brightness to the walls and ceiling.
Lighting: ARP, Lighting: Lamps, Lighting: Installations

Street Lighting Notes p7
Brief description of the installations at: Bolton, Burley and Bradford.
Lighting: Installations

The Royal Society For The Prevention Of Accidents p7
The Quarterly Meeting of the National Public Safety Committee of the R.S.P.A. was held on January 23rd, at which Captain Liberty was present as representing the A.P.L.E. It was an important meeting as Colonel The Rt. Hon. J. J. Llewellin, C.B.E., M.C., M.P. (Joint Parliamentary Secretary, Ministry Of War Transport, President Of The Board Of Trade) who is Chairman of the Government Committee on Road Safety in War - attended the meeting to hear progress of the Winter Road Safety Campaign. After hearing reports, Colonel Llewellin promised Government support to the campaign.
A report received from the Management And Finance (War Emergency Committee) on the Minsitry Of War Transport Committee on Road Safety In War, noted that during the four "black" months of September-December 1941, some fewer 900 fewer persons were killed in road accidents as compared with the same months the previous year.
Lighting: ARP, Lighting: Safety, Lighting: Statistics

Electrical Development Association p8
The annual luncheon of the Electrical Development Association was held on Friday, March 20th, at the Savoy Hotel, London. The President to the Board of Trade, The Rt. Hon. Huge Dalton, M.P. gave a speech where he congratulated the Electrical Industry for the part they played in the war effort. He paid a high tribute to the "grid system" which enabled war industries to be built up in remote areas in a way that would not have previously been possible.
Lighting: ARP, Lighting: Safety, Other

The Late Mr. J. H. G. Horstmann p8
Obituary for Mr. John H. G. Horstmann, Director and Secretary of the Horstmann Gear Company. His family have been associated in business in Bath over the last 100 years. He was 45, and succeeded his father as secretary of the company some 12 years ago. He was a member of the Society of British Gas Industries and was a prominent advocate of domestic and street lighting.
Lighting: Personnel

Claims Against Government Vehicles p8
It does nto appear to be clearly understood that the Government accepts financial responsibility in the case of damage to property resulting from accidents in which Government vehicles are involved, provided it can be shown that the accident was due solely to the negligence of the driver. This was made clear by Sir Stafford Cripps in the House Of Commons.
Lighting: Legal

The War And Patents Relating To Public Lighting by S. T. Madeley p9
What are the inventor's prospects of getting a patent granted? And what is the recent trend in this direction?
The Patent Act of 1907 had no provisions to meet the case of hostilities, the First World War had largely to be met by improvisation, including the grant of temporary licences under enemy patents. The Peace Treaty had to straighten things out. To reward inventors in connection with the war, a Royal Commission was appointed. Into the Patents And Designs Act of 1919, there was introduced Section 18(6) where a patentee was entitled to apply for an extension of term of his patient solely on the ground of loss of damage due to hostilities. As a general relief, the term of the normal patent's life was extended from 14 to 16 years subject to renewal fees.
To assist inventors and patentees on the outbreak of the present hostilities, the Patents, Designs, Copyright and Trade Marks (Emergency) Act, 1939, was passed. The Comptroller-General has wide powers under this act.
The Comptroller is enabled by section one of the Act to revoke or vary a licence, granted under a patent for a street lamp owned by an enemy or an enemy subject. Section two empowers him to grant a compulsory licence to a suitable applicant under similar circumstances. Under section four, patents can still be filed under the International Convention by enemies. As a general rule, those applied for by enemies will only be allowed to proceed to the acceptance stage. Section six empowers the Comptroller to grant extensions of time for late filing of documents, payment of fees, where in his opinion, circumstances arising out of the war justify such a course.
This Act should afford inventors and patentees much needed relief, especially when coupled with section 18(6).
An invetion of a really good ARP street lamp is worthy of considerable recognitiion by such Royal Commission for Awads, as may function after the war.
The Patent Act is also due for reform. The Patent term should be extended to eighteen years. Two years instead of one should be allowed for filing a complete specification after provisional. Basic Convention documents should be more liberally construed and patent litigation should be simplified and cheapened.
Lighting: ARP, Lighting: Legal

An Unlighted Bollard from the Manchester Guardian p10
A crash into a bollard on an island refuge in London Road, Coventry, on October 24th, 1940 raised an interesting legal point under the lighting restriction orders. On leaving London, one of William Henry Bowker's drivers, had been required to put out his headlights owing to an "alert". He reached Coventry not knowing whether the "all clear" had been given. He ran into an island bollard, which was unlighted. Mr. Laski, for the Coventry Corporation, could not contest the point that the island bollard was unlighted, but the plaintiff could not succeed if there were any contributory negligence. Next, the corporation was under no obligation to light since the lighting regulations came into force. The latest case, Fox vs. Newcastle Corporation was on its way to the House Of Lords on the question of whether the public were bound to be protected against an obstacle such as an air raid shelter. Counsel stated that the occasion of the accident was the end of the Coventry blitz. There were 42 instances of damage to the gas installations and it might well have been that the gas pressure was not sufficient to keep the bollard alight. Mr. Rowson, for the plaintiff, contended that there was no negligience on the part of the plaintiff and the unlit bollard was a trap and a nuisance.
The Judge found that, owing to enemy action, the bollard was not lighted but Bowker's driver was driving blind because when leaving London for Liverpool he had been warned of an "alert" and was told not to use headlights. At 1:30AM, there was no "alert" on at Coventry, but the driver made no inquiries and was still driving blind at 15 miles an hour. Such a speed was a great deal too fast when driving blind, and the driver failed to see this great white object. There was negligence on the part of the driver and Bowker could not succeed.
The Judge also found that the corporation had been negligent in not taking reasonable care to light the bollard or warn drivers. Therefore they contributed to the accident. Judgment for the Coventry Corporation was with costs.
Lighting: ARP, Lighting: Legal

Strange Use Of Fluorescent Light from The Atlantic Monthly p10
The fact that various inks and glues fluorescent under ultra-violet light provide a new way to detect forgery, alteration of documents, and tampering with the mail. Butter and margarine may look alike under daylight but under ultra-violet margarine is blue. Fresh eggs have a red fluorescent, but after ten days become reddish brown, then blue. Other foods may be tested in the same way. Government experiment stations detect fungus infections and other plant diseases by the fluorescence. Ring rot in potatoes has been detected this way. Pathologists can detect different species of bacteria by their colour.
Lighting: Lamps

Adverts: The General Electric Co., Ltd, William Sugg And Co., Ltd., Siemens Electric Lamps And Supplies Ltd., The British Thomson-Houston Co. Ltd., British, Foreign And Colonial Automatic Light Controlling Co., Ltd. APLE, Annual Report Of Light Undertakings and Metropolitan Vickers Electrical Co. Ltd.