38 ANNUAL OF SCIENTIFIC DISCOVERY. 



tween the blocks were found to be in every gradation between the 

 perpendicular and the horizontal, without coinciding with either of 

 them. In this obliquity of the joints the author detected the arch 

 principle of construction as applied to the work, and the workmen 

 pointed out to him, that each stone either pressed or supported, with 

 every one of its sides, however numerous. Generally, the writer 



*/ / 7 



holds this polygonal or Cyclopean kind of building to be especially 

 applicable in, first, hydraulic works, as it offers nowhere a continuous 

 joint to the water; second, in fortifications; third, for railways in 

 substruction and steep coverings, and in the cellar story and even in 

 the next story of large buildings and palaces. In these mortar would 

 be used, not as a means of connecting the stone, but only as pointing 

 to the joints, so that the immediate contact of the stone should not be 

 interrupted. In conclusion, the writer recommends the adoption of 

 this method of building according to determined and clearly defined 

 principles and rules, as altogether practical, wherever the material for 

 polygonal blocks is found, a method which is at least to us a new 

 one, and not simply a more careful execution of the long-used rock 

 walls, or an ornamental imitation of an old style. London Builder. 



WHITE'S WOODEN SUSPENSION BRIDGE. 



BY this invention the Patentees claim to have solved the problem 

 of spanning broad and rapid rivers with a structure which requires no 

 piers, yet is suitable for railroad purposes, and can be built at a rea- 

 sonable and practical cost. The principal feature of the invention is 

 the substitution of wooden stringers constructed of boards cemented, 

 dowelled and bolted, for iron chains or wire cables. There is no 

 question as to the strength which may thus be attained ; a reference 

 to any tables of the strength of materials will show that the tensile 

 strength of hard wood is much greater in proportion to its weight than 

 bar iron. Any number of these stringers considered necessary for a 

 given structure may be placed one above another and each be firmly 

 anchored beyond the points of support, by back stays fastened into 

 the abutment ; the, only question seems to be, whether the stringers 

 can be locked to the back stays with a sufficient degree of firmness. 

 The principal advantage which is claimed for this invention is that it 

 can be entirely freed from that tendency to vibration, which is fetal to 

 the use of the iron suspension bridge upon railroads. The means used 

 to effect this are very simple, and certainly seem to be effectual. 

 Perpendicular oscillation is partly overcome by springing a direct arch 

 from one abutment to another which in the centre rises nearly to the 

 road bed, and which is firmly connected with the stringers above by 

 the suspension rods which sustain the floor ; and lateral oscillation is 

 overcome partly by making the bridge diminish in width from the 

 extremities to the centre ; while all possibility of vibrations would 

 seem to be avoided by the mode of covering. This is done as follows : 

 the entire 1 structure-, is covered with a double diagonal bonrding, and 

 the planks of the road bed are also laid double, crossing the floor joists 

 also diagonally. 



