and glassware. The most efficient of the smaller multiple lamps take considerably more than a watt per candle-power, while the high-current Mazda C lamps burning in series require as low as one-half watt per candle. In addition to its many advantages from an operating standpoint, the singlelight post is admittedly superior in appearance to the cluster post, adding to the beauty of the street under both day and night conditions. It relieves the street of the crowded appearance resulting from too many small lamps and gives an effect of simplicity and elegance combined with illuminating efficiency of the highest order. Cluster posts have been objected to on the grounds that they are often only partly illuminated on account of the burning out of lamps.

Noteworthy advancement has also been made in the design of pendent fixtures, whereby refracting or diffusing glassware may be used to suit the requirements of each individual case. It is thus possible to control the distribution of light so that it may be utilized to the best advantage.

Lighting System Varies With District City streets may be divided roughly into three classes according to the amount of light required and the type of fixtures generally employed: 1, business districts; 2, main residence streets; and 3, side streets and outlying districts.

Business districts are usually lighted, at least in part, by "White Way" systems, using ornamental posts at intervals of 75 or 100 feet on both sides of the street. The posts may be "staggered" or placed directly opposite each other, depending somewhat on the width of the street, the spacing distance, and the amount of light desired. Power is distributed to the posts by means of armored cable, usually buried under the paving at the edge of the curb. The posts are preferably connected in series on a constant current circuit, so that only a single wire need be run from post to post, and the current is controlled by a moving coil regulator located at the nearest distributing center. Lamps ranging from 400- to 1,000candle-power are commonly used. A higher intensity of light is usually desired than is necessary from a strictly utilitarian standpoint. One of the principal objects is ornamentation, and considerations of economy

and scientific arrangement are often ignored. The popular conception of a "White Way" implies an intensity of light almost comparable with daylight, and to fulfill this condition the lamps are mounted not more than 12 or 13 feet above the sidewalk. It seems to be pretty well agreed among competent observers that mounting heights of 20 feet or more produce the highest visibility and give the most satisfactory results in general, but such mounting heights are not usually considered compatible with the requirements of real "White Way" lighting.

Night and day views of 14th Street, Denver, Colo., are shown herewith. The standards are equipped with 600-candle-power lamps, and stand approximately 75 feet apart, directly opposite each other. As seen from the night view, the street has a neat, uncrowded appearance, and there are no unsightly arms projecting from the posts to obstruct the light and cast shadows. It is not uncommon for motor trucks and other heavy vehicles to collide with posts along the sidewalk, and ornamental posts must be constructed to withstand such abuse. It is easily possible to build posts of cast iron with sufficient strength to resist a shearing stress of 30,000 pounds per square inch, and such posts, if protected by weatherproof paint, offer excellent resistance to corrosion and may be made to last indefinitely.

The detailed construction of the post top most commonly used is designed so that a large percentage of the light is directed to the surface of the street and sidewalk, altho there is enough light available in an upward direction to illuminate the façades of buildings. The enclosing globe is of sufficient density to conceal the lamp filament and soften the light without greatly reducing the efficiency by absorption. The porcelain-enameled steel reflector placed over the lamp saves a good part of the light by redirecting most of the upward rays, which would otherwise be lost by absorption in the top of the fixture. The entire top is designed with a view to obtaining the maximum of useful light from the lamp and at the same time having a distinctive and ornate appearance.

It is often the case that business streets are traversed by trolley lines, necessitating the use of trolley poles on the sidewalks. Where ornamental posts are installed in addition to the trolley poles, it sometimes

spoils the symmetry of the street and gives it a crowded appearance. This may be avoided by the use of ornamental trolley brackets.

Such an installation is shown in the accompanying photograph, where the five-light cluster posts are being replaced by single-light bracket units mounted on the trolley poles. A considerable increase in illumination will thus be obtained at a lower cost, and without marring the beauty of the street. The bracket is essentially the same as an ornamental post as far as the lighting element is concerned, and differs only in the method of support.

Boulevard Lighting

In many cities ornamental systems are used on the most popular boulevards, carrying a relatively large amount of traffic. In such cases, greater economy must be practiced than in the business district; a somewhat smaller lamp is used, and the spacing distance increased. By "staggering" the posts, it is possible to widen the spacing and maintain a more uniform intensity of light.

Lighting the Residence Streets

In lighting residence streets, the main object is to furnish enough light to see by, without special regard to ornamentation or advertising effect. It must be possible to make one's way about at night without inconvenience or danger from collision or attack. To accomplish this result at a minimum of first cost and maintenance expense is the problem of residence street lighting, and any features tending toward a more efficient utilization of the light are favored by the designer. By higher mounting of the lamps-20 to 25 feet above the streetthe light source is removed from the range of vision, resulting in greater visibility. It has been estimated that the hanging of lamps unnecessarily low has the effect of wasting probably half of the light emitted, because the ability of the eye to see objects beyond the light has been impaired in that proportion. Furthermore, high mounting of the lamps causes the light to spread farther up and down the street, tending toward greater uniformity. Spacing distances ranging from 150 and 200 to 400 feet are commonly used. This feature is determined largely by the size of lamp, and the type of glassware used with the fixtures. These lights are operated on series circuits, and when equipped with small auto current

transformers make use of the high-efficiency 15- and 20-ampere Mazda C lamps.

Because of the high current, it is possible to build the lamps with short, stocky filaments capable of operating at a more intense heat than the slender, delicate filaments of the low-current lamp. Temperature is the determining factor in efficiency of light production. The fixture casing is made of cast iron galvanized and coated with weatherproof paint, so as to withstand the most severe conditions of weather and handling. The fixtures may be suspended from mast arms of sufficient length to clear the trees, or from a cable stretched across the street.

Choosing the Glassware Medium The glassware used with pendent fixtures of this kind may be one of two common types known as refracting and diffusing glassware. Refractors, as the name implies,

ARC LAMP SUSPENDED FROM MAST ARM OF SUFFICIENT LENGTH TO CLEAR TREES

redirect the light by bending the rays, and cause a large portion of the light to shine at an angle of 10 or 15 degrees below the horizontal, thus increasing the intensity at points midway between the lamps. With diffusing glassware, however, no attempt is made to change the direction of the light but simply to break up the rays and soften the light by furnishing a light source of lower intrinsic brilliancy without losing more than 15 per cent of the light by absorption. With refractors, the ratio of maximum to minimum intensity of illumination on the street surface is relatively low. With certain types of refractors it is possible to have the best lighted areas on the street not more than eight times as bright as the darkest points. With diffusing glassware, this ratio may easily be several hundred to one, unless the lamps are placed unreasonably close.

The relative merits of the two types of glassware have been the subject of a great deal of discussion among illuminating engineers for a number of years, some claiming that uniformity of intensity is not essential or even desirable for good visibility and that objects midway between lamps may be

distinguished by their dark outlines against the light background of the next lamp, and others maintaining that objects can be seen and recognized more readily and accurately by the direct illumination they receive than by their silhouettes against a light background.

It is now pretty generally believed that

there are some valuable features in connection with each of these types and that most satisfactory results can be obtained with fixtures which combine the two principles. It is thought to be inadvisable to rely solely on silhouette lighting with a high ratio of intensities, because it is difficult for the eye to accommodate itself to widely varying intensities, and, furthermore, a certain amount of direct illumination is essential in distinguishing the details of an object or recognizing a person. A number of methods have been devised for combining the principles of refraction and diffusion, and one of these is the skirted type refractor. The upper portion of the refractor is made up of the usual refractor prisms for redirecting the light, while the lower section. is simply a skirt of diffusing glass.

The prismatic section serves to increase the horizontal intensity and the illumination at points midway between the lamps, while the diffusing skirt softens the light which strikes the street around the lamp, avoiding glare and strengthening the illumination near the lamp to the extent of permitting some degree of silhouette effect.

The less important residence streets and outlying districts, where traffic is light, are usually lighted by streethoods suitable for lamps ranging from 60 to 400-candlepower. They are ordinarily operated on 6.6 ampere, with a film cut-out socket, which automatically short-circuits the lamp when it burns out, thus protecting the other lamps on the circuit against interruption.

The fixtures may be suspended from brackets, mast arms or cable, as the local conditions may require. Streethoods have been used mostly without glassware in the past, in spite of the glare and the objectionable appearance of the bare lamp, because of the increased cost involved in equipping the fixtures with glassware.

Where there is ample light

A

CONTRACT for the purchase and final disposition of garbage by feeding was awarded to the National Utilization Company by the city of Newark on July 3, 1919, for a period of five years commencing September 1, 1919. The price to be paid to the city for each ton of garbage delivered is eight times the price per pound of live killing hogs on the Chicago market, as determined by averaging the top price for each month.

The piggery is to be located along the shore of the Passaic River, and the city wagons are to deliver all garbage to the feeding site, where it will be weighed. The city agrees to the enforcement of existing ordinances, to effect a good primary separation, and also agrees to endeavor to pass ordinances whereby the contractor will receive all hotel and restaurant garbage.

The collection of all city refuse was done by contract until 1916, when the contractor terminated the contract on the ground that the separation ordinance was not enforced. The contract was then taken over and carried on by municipal forces. For several years past there has been a rather unsuccessful attempt to separate garbage from other refuse. In March, 1919, a new ordinance was introduced requiring the separation of ashes, rubbish and garbage. At the present time separation is effective thruout the city, collection being made in refuse wagons having separate compartments. A police officer and inspector is assigned to each district to enforce this ordinance, and the results have been very gratifying.

The erection of a reduction plant of 150ton capacity was contemplated, but the

present cost of building material is considered prohibitive. An estimate received from one company was $750,000 exclusive of the cost of the site. The city has some 6 square miles of meadow land, and all classes of refuse have formerly been dumped on this land. There is a contract for the salvaging of the material, for which privilege the city receives $3,000 annually. The contractor also supplies all labor necessary to keep the dumps and the roads leading thereto in good working condition. Now that separation is completed in the entire city, it is planned to erect a utilization plant for rubbish and to deposit only ashes on the meadow land. The area of the city is 23 square miles, and the estimated population 450,000. It is estimated that 5,000 hogs will be required to consume the maximum amount of garbage during the peak months of summer.

On account of the limited area available at the site of the piggery, intensive methods will be employed. The hogs will be housed in unit buildings 100 x 100 feet, which will accommodate from 800 to 1,000 hogs. A double concrete driveway and feeding floor 24 feet wide extends thru the center of each building, with a gutter on each outer edge next the pens. The gutters discharge into large grease traps, to prevent solids reaching the sewer. The pens are arranged on either side of the driveway, having a slight pitch toward the gutters. There are five pens on each side equipped with automatic drinking fountains. Each pen opens into a yard 50 feet deep. The houses are of sawtooth type, with windows the entire length below the eaves and in the peak.