CHAPTER III 



THE CLEANING OF PAVEMENTS 



THE physical appearance of the dirt of the streets 

 varies considerably. Some of the large portions con- 

 sists of pieces of rejecta which can easily be 



Physical 



Properties of removed from the pavement by scavengers 

 with hand tools, such as shovels and brooms. 

 Fragments of garbage, of paper and fresh horse dung 

 belong to this class. 



Other particles of street dirt are too finely ground up 

 to permit of separate hand removal, as ashes, for ex- 

 ample, and horse droppings after they have become 

 scattered by traffic. In this class, also, is much of the 

 sand, earth, and coal dust which are dribbled from 

 overfilled wagons or allowed to get upon the streets 

 through carelessness. 



This finely ground material is the most difficult and 

 expensive kind of street dirt to deal with. Its thorough 

 removal is too often neglected in street cleaning. It 

 forms a slippery, sloppy mud in wet weather and a 

 blinding dust when the weather is windy and dry. It 

 is necessary to deal with this material in some special 

 manner in order to get rid of it. That manner depends 

 upon the pavement, the amount of dirt to be dealt with, 

 the particular uses to which the street is put, the abund- 

 ance or scarcity of water available, the price and relia- 

 bility of labor and the condition of the sewerage system. 



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