MECHANICS AND USEFUL ARTS. 123 



this style of building is the cheapest of all, and in most cases ap- 

 plies to our wants and climate, and to the desired architectural 

 arrangements, and is applicable to any material." 



• • * *' The advantage of the concentration of the whole 

 mass on piers will at once be visible. A pier has more elasticity 

 than a solid wall, and if placed isolated, in the proportion of 

 about 8 times the height to its base, this pier would, by a slight 

 movement of the earth, lose its point of gravity ; but by connect- 

 ing a number of piers horizontally, transversely, and longitudi- 

 nally, and by resting the weight of the whole building upon 

 them, they become restrained in their natural action till the whole 

 mass of the building begins to move. 



" That piers will facilitate the rapidity or velocity of the move- 

 ment of the whole mass, nobody will deny ; inasmuch as they 

 stand isolated, are comparatively weaker than a solid wall, and 

 have solely to depend on themselves, in their own strength and 

 nature, without any assistance from a connecting wall. It is 

 hardly necessary to mention that the piers should, of course, be 

 in proportion to the weight they have to support, and should be 

 placed at proper distances for security." 



• • • '* To many it may seem strange that the towers of San 

 Francisco stood so well during the late earthquakes, with hardly 

 any apparent damage, and that also in European cities the tow- 

 ers have also been less injured ; a fact which proves, in a most 

 striking manner, that the flexibility or elasticity of a mass is a 

 necessity for safety. A tower is a pier of high proportion, and 

 forms a high pendulum, and naturally swings with more rapid- 

 ity than a longer mass, and hence there is less danger. The 

 tower of the Doin of Erfurt, at present a fortified city in Prussia, 

 contains the largest bell in the world except the celebrated bell in 

 Moscow. This bell requires 24 men to set it in motion, and when 

 in motion has always caused an oscillation of the tower varying 

 from 4 to 5 feet from the perpendicular line. For centuries this 

 bell has been used, and the tower remains as perfect as ever. 

 This tower is built of cut stone, with the finest details of Gothic 

 architecture. I merely give this example to show the flexibility 

 even of stone, provided the proportions are right. 



" All our hotels stood well, also a large number of stores; in 

 fact all buildings supported on piers or columns. All the bodies 

 of churches also stood well, especially where buttresses were in- 

 troduced. Each buttress forms a pier, and has, consequently, 

 more elasticity, and always will stand well, provided the propor- 

 tions are artistically carried out. Very low churches, built more 

 in the proportions of a stable, are unsafe ; in fact, all buildings 

 one story high, and of considerable extent, are liable to danger, 

 more so than two or three story buildings, no matter of what mate- 

 rials soever." 



WATER-PROOFING WALLS. 



One of the most recent of the many uses to which Mr. Freder- 

 ick Ransome's process of manufacturing artificial stone has been 



