WEATHERPROOF LANTERNS FOR STREET AND YARD LIGHTING

FC. 6046/7 THE "WEMBLEY" LANTERN

SECTIONAL ELEVATION OF "WEMBLEY" LANTERN

BODY.
Spun from heavy gauge sheet copper, enamelled green outside, and white inside for relfecting surfaces with copper top and ventilator.

VENTILATING DEVICE.
A patented device operating on the ejector principle is fitted combining extreme simplicity with high efficiency. This device causes a steady stream of air to be drawn into the lantern and ejected from beneath the top cowl. Exhaustive tests have been carried out with this ventilating device, special attention being given to lamp performance. The result of these tests demonstrates convincingly that the ventilation is such as to safeguard the lamp from overheating and consequent reduction in normal life.

WEATHERPROOF CONSTRUCTION.
The development of the "WEMBLEY" lantern to its present high state of efficiency was accompanied by periodical tests to prove that it was absolutely weatherproof.

FOCUSING DEVICE.
This is a special patented feature which enables the lamp to be raised or lowered inside the prismatic refractor, thus varying the distriubution of light to suit the height and spacing of units. All such adjustments in the larger size "WEMBLEY" lanterns are made from the outside without opening the lantern in any way. The lamp is lowered until the filament is sighted across the bottom edge of the refractor; the knob is turned a predetermined number of times to the right, and adjustments can be made to the 1/100th part of an inch.

OPTICAL SYSTEM.
The "WEMBLEY" lantern is made in various sizes, designed to accommodate OSRAM gasfilled lamps or either 100 watts or 1500 watts, suitable for main thoroughfares, suburban streets and residential areas. It is equipped with a prismatic glass refractor and white enamelled over-reflector, the lamp and refractor being protected by a clear glass outer globe.

PERFORMANCE.
The light emission is ideal for street lighting, the maximum candle-power being given at the useful angle of 70° from the vertical. The resultant illumination curve from two such units suspended at a height of 25 feet from the ground and spaced 100 feet apart is shown by the curve below.

The values shown are obtained on a horizontal plane 3 feet above ground leve, and it will be seen that the maximum illumation occurs at aprrpoximately 4 feet from the base of the standards and is 2.89 foot-candles. The minium illumination is 0.90 foot-candle and the average intensity is 1.75 foot-candles. Thus, with a spacing ratio of 4 to 1, which is in accordance with the best modern practice, an inequality ratio (i.e. maximum illumination divided by minimum illumination) of 3.2 to 1 is obtatained - a highly satisfactory figure. Distriubtion curves of other models will be furnished upon request.