236 [Assembly 



rolled in the manner as described for the pebble pavement, but even 

 such a manner is only of service where the traffic or travelling is 

 slow, and will not stand against the destructive power of the violent 

 concussions produced by rapid travelling. I find in the communica- 

 tion to your honor from the committee appointed, an inquiry respect- 

 ing the experiments recently made in the city of New- York, and as 

 I deem that enquiry refers to the " Russ Pavement," I would refer 

 to a description of said work, which may be found in the " Report 

 of the American Institute," to the Legislature of the State of New- 

 York, April 20, 1847. I would also refer to a communication from 

 ex-Mayor Harper to the Common Council, January 6, 1845, con- 

 taining a minute description of the manner of constructing the square 

 block pavement in the city of London, a copy of a part of which is 

 herewith inserted: " An excavation is made from gutter to gutter to 

 the depth of twenty-four inches, the space excavated is filled with 

 concrete to the depth of fourteen inches, rising towards the centre at 

 the rate of six inches in twenty feet. The concrete is made of 

 granite clippings or granite ballasts (the same that is used for Mc- 

 Adamizing roads) and sand and hychaulic lime in powder, six parts 

 of the former and one part of the latter, which when properly mixed 

 sets and becomes a hard solid mass. The surface must be made 

 smooth, and when set the mass of concrete serves as the foundation 

 of the pavement. 



" The pavement is either of wood or of granite, the latter is here 

 recommended. It is composed of blocks ten inches in length, ten 

 inches in depth, and five inches broad, rough on the upper surface 

 and sides, and the latter tapering very slightly towards the bottom. 

 They are laid diagonally (see plan) so as to give horses a good foot 

 hold and prevent them from slipping." _ 



" They are not pounded (for this would break the surface of the 1 

 concrete) but merely laid side by side in regular order. The inter- " 



stices are then filled with liquid mortar, which adhering to the rough 

 edges spreading a little at the bottom, and combining with the con- 

 crete beneath, forms the whole into a solid mass twenty-four inches 

 thick, not likely to be broken, and capable of enduring unshaken 

 almost any amOunt of travel by the heaviest vehicles." 



In the description of the different materials given above, granite 

 is always referred to as the class of stone proper for pavements, but 

 it is not always the best material. Gneiss is frequently used for 

 pavement under the same generic term of granite. This is still ob- 



