iKTo SEWERS. 



149 



fand com'eyed by the wind will f;ill through the aperture 

 of the lid into the pan, and will loon fill it and cloi'e the 

 aperture, fo that all the fand which follows will blow 

 over and pafs off. When it becomes neceflary that the 

 aperture fliould be re-opened to let the water of the 

 drains pafs through, that water will itfelf very quickly 

 work its own way through the fand in the pan, wafli it 

 over the hrim, and down through the hopper and flioe 

 into the fewer, and reftore the water paffage ; and thus 

 the wind and water will alternately perform the fundlions 

 of clofing the paffage againft fand, or opening it for wa- 

 ter as fhall be neceffary. 



^ 



c 



LLl^t 



B 



D 



In the two fe£tions here reprefented 

 A B C D is the opening of the fewer into the ftreet. 

 E F the curb at its orifice. 

 G H I K the hopper. 

 L M the fhoe. 



In the fecond figure NOP Q^is the fand-lid of the 

 orifice, and O P the aperture in that lid. R S the pan 

 fufpended under it. 



Vol. V, 



X 



No. 



