Plan for Building the Arcade without interruption to travel. 



Tlie work on the Arcade will be commenced by placing along the line of 

 the roadway, two iron bridges of about 300 feet in length, and each 18 feet 

 wide in the clear, and along the line of sidewalks corresponding bridges 

 each about 12 feet wide. These bridges to»be supported at intermediate 

 points. 



The floor of these bridges will be elevated four feet above the grade of 

 the street, and the difference in elevation overcome by a gentle ascent at 

 each end. 



These trusses are skeleton frames, and will form but slight obstruction 

 to the view, and will permit pedestrians to cross the streets at all places. 



The panels are made separate and bolted together, and may be takea 

 down from one end and added to the other with great facility. 



Convenient access to and from the bridges will be provided for, and the 

 work on the railway will be carried on beneath, without using the street 

 either in the removal of excavitions, or in bringing materials to construct 

 the road : the completed Arcade being ample for these uses, and affording 

 abundant store-room for all the purposes of construction. 



The street in front of an ordinary building would be occupied by the 

 bridges and workmen about one month, and during this time (by the plan 

 proposed) the occupants of the building would suffer but little incouvenieuce, 

 and the street travel little, if any obstruction. 



