(11) Existence of markets 125; or (12) Push-cart stands 175.
(13) Vicinity of unpaved streets 200.
That a street bears heavy traffic is seen to have more influence on the labor of sweeping than that it has granite instead of asphalt pavement. The amount of traffic affects the cost; but no other single cause contributes so much to the difficulty and expense of sweeping as the action of careless and thoughtless per sons in making the public streets the receptacle of all kinds of rubbish fruit parings, bits of paper, etc. of which they wish to be rid, and which a little consideration would induce them to deposit in some can which might be emptied into a cart without the trouble of sweeping and shoveling from the pavement.
Machine sweepers (horse or automobile) lessen the cost of street cleaning, and may be used to advantage with preliminary sprinkling on wide, level, well-paved streets, between mid night and dawn; but their service on crowded streets in daytime is impracticable.
A fall of snow is such an impediment to city traffic, which is usually conducted on wheels even in winter, that it is recognized as a duty of the departments of street cleaning to remove it promptly from important streets, especially from the lines of daily food distribu tion and from the avenues of daily approach to the business districts. The numbers of men and teams suddenly required are very large, and dumping facilities are in general quite inade quate to the work. The cost is also great about $125 per mile of streetper inch of snow, or $1,250 per mile of street for a 10-inch fall. For these reasons numerous efforts have been made to develop practical processes for melting the snow as it lies, or at least -on the block where it lies, and running the water into the nearest sewer opening. Machines for the pur pose have been tried in many cities for many years, but have usually proved unequal to the task, because of the cost of melting. The most satisfactory method where there is plenty of water in the city pipes, that is well above the freezing point, is to turn a hydrant hose on the snow and wash it down the gutters. Of course this method is applicable only to a light fall, or to the remnant of a heavy snow fall.
In all street dirt disease germs lurk in un known numbers, and when the dirt is dry and dust is raised by passing traffic or by winds, the dust and the germs find lodgment in eyes, nostrils and mouths, and the work of disease is begun. Of course the dust and the germs
are the thicker the nearer the pavement, and no other cause is necessary to explain why the children of the crowded streets are so affected. Careful experiments carried out in New York by Commissioner Woodbury, with germ cul tures from plates exposed, some at the curb level and some at six feet above, exhibited a wonderful difference in the number of germs which found lodgment on the plates in differ ent parts of the city. At the curb level the evi dence of the plates showed on the average five times as many germs as at six feet above. In a tenement district densely, opulated, where push carts are numerous and traffic heavy, as matiy as 9,600 germs were caught in a 15-mlnute ex posure of a plate two and one-fourth inches in diameter. In another part of the city, in a residential district, with heavy traffic but well flushed pavement, only 54 colonies were found after a 15-minute exposure.
The relative costs of street cleaning in dif ferent cities of the world are impossible of comparison, because the conditions and the standards of cleanliness vary so much, and be cause the work of the department has nowhere been reduced to an exact science. But in gen eral the cost in Europe is much less than in America because of the greater waste and care lessness of the average American citizen, and because of the lower wage cost in Europe. The cost of street cleaning in Manhattan and the Bronx, including the collection and removal of house waste hut not the removal of snow, be fore the war prices set in was about $7,000 annually per mile of street. In Vienna, where only some 25 miles of street in the heart of the city is kept thoroughly clean, the annual cost, excluding snow removal, was about $5,000 per mile. In Budapest, where the pavement is ex cellent and where much value is recovered by sorting the wastes, the annual cost was not far from $2,000 per mile. In Paris it was about the same. In Brussels the cost was about $1,350 per mile. In Birmingham, England, the cost was still less, though wages were higher than on the Continent See WASTES, Crnr, DIS POSAL OF.