€34 REPORTS OF THE BUILDING COMMITTEE. 



"WALLS OF BUILDING ABOVE FOUNDATION. 



Stone masonry. — The walls shall he faced with the best broken rubble masonry, of 

 white marble, or buff-colored Seneca stone of even color and best description, or of 

 granite similar to that in the rear of the General Post Office ; and the contractor will 

 state in his estimate the expense of constructing the building with each of the three 

 above described materials. The face of the stone shall be brought to the square by 

 the mason's hammer, care being taken to pick, as far as possible, such stones for the 

 face as will require little dressing ; the object being to preserve, as far as practicable, 

 the natural face of the stone, with the crystals unbroken. The beds, joints, and 

 builds of the stone shall be dressed true and even, so that the joints shall not exceed 

 one-half of an inch in the widest place. The style of the front shall be either broken 

 or angular rubble, and the face shall be laid in the manner directed by the architect. 

 The facing shall average ten inches in thickness, and no stone will be allowed in the 

 work whose breadth of bed is less than two-thirds its height. The stone shall be of 

 nearly uniform color, free from all sap, iron pyrites, and all other discoloring or 

 deteriorating material, and especially in the white marble, from the decomposing car- 

 bonate of magnesia. 



The face of the wall shall be strongly tied to the backing by headers of the same 

 material as the face, running in places through the wall, and in no case less than 

 twenty inches in depth, and furnished in such numbers as the architect shall direct — 

 say one in every three feet six inches square. All the arres of the buttresses, towers, 

 &c, and all the corners, splays, and angles, throughout the whole building, shall be 

 dressed with the chisel so as to be perfectly plumb, true, and even, when laid. No 

 quakers will be allowed in any part of the work. All the stones shall be laid on their 

 natural beds. The heading stones on the corners of all the towers, buttresses, and of 

 the whole building, shall have beds at least equal to their heights on face. The joints 

 shall be pointed with a mixture of the best quicklime and blacksmith's scales and 

 sand, and shall be smooth struck on the face ; and, after it has set throughout, the 

 joints shall be painted to the color of the face with the best pure white lead and boiled 

 linseed oil, colored to the color of the stone. All the walls will be backed in with 

 best blue gneiss, of good shape and size, laid on the natural bed, and well bonded to 

 the face work. Behind the outside walls, and at a distance of four inches from them, 

 a five-inch brick wall, tied to the outer wall by at least one bond stone in every three 

 feet square, will be laid. This backing will be returned, to meet the front wall at all 

 the jambs and arches of all the windows and doors. It will also be tied to the front 

 walls, in the piers between the windows, by brick cross walls nine inches thick, to 

 form the flues ; which flues will be constructed as follows : In each of the piers 

 between the windows there will be three flues 8 by 16 inches in the clear inside, which 

 will be carried from a point three feet below the under side of the beams of the first 

 story to the top of the building. One of these flues will be connected with the fur- 

 naces by a horizontal flue of galvanized iron, or double-cross tin, two feet square, 

 which will be furnished by the contractor, for the purpose of diffusing the hot air 

 throughout the building. All these flues will have neat registers in the rooms, for 

 the proper regulation of the heat. The second flue will have an opening in each 

 story, on the line of the ceiling, on the outside of the wall, and another opening into 

 the bases of the rooms inside ; these will admit the cold air from the outside of the 

 building into the respective rooms for the purpose of proper ventilation, and will be 

 closed up on the level of the floor of each story, by a cross wall over the outside open- 

 ing ; and each of the above flues will be furnished with a heavy sheet-tin slide-valve, 

 with proper fixtures for opening and shutting, placed in such part of the flue, and 

 made in such manner, as may be directed by the architect. 



The third flues will have openings on the inside on a line with the ceilings of all 

 the rooms ; through these the foul and heated air will be carried off and discharged 

 by an opening under the coping of the building. All these flues will be furnished 

 with two sheet-tin valves each, made and placed in the manner directed by the archi- 

 tect. Proper flues, well parged, will be carried up for the furnaces, fireplaces, engine, 

 laboratory, &c, in such places as may be directed by the architect. 



In addition to the above ventilating flues, openings with valves will be formed in 

 all the groined ceilings, which will be connected with the corner towers and flues in 

 the larger towers. 



Thickness of walls. — The thickness of the walls of the main building above the 

 water tables will be two feet six inches in the first story, and two feet in the second 

 story, exclusive of all projections of the buttresses, corbel courses, battlements, 

 bands, &c. 



The thickness of the end walls of the main building will be two feet six inches for 



