Mr Robertson on the Mechanical Arts of Persia. 305 



limestone, including the stones used in forming the dome. 

 The ashes are used in the manufacture of soap. 



"With a few improvements, this kiln might be used econo- 

 mically for burning lime, where peat is abundant, and even 

 in most large farms in this country, as much wreck and clip- 

 pings are burned on the ground every year, as would be suf- 

 ficient for calcining several kilns of limestone in this simple 

 manner. 



BaUding. — Almost all the buildings in Persia are constructed 

 either of clay or bricks. 



Clay-Bivilding, — The clay is generally procured near the 

 intended erection, and is brought to the proper consistency by 

 mixing with water and treading with the foot. For walls, a 

 foundation is cut out as far down as the vegetable mould, and 

 this trench is filled up with small stones and clay. The walls 

 are built in courses, of about one yard in thickness, each 

 course being allowed sufiicient time to consolidate before an- 

 other is laid. The workman stands upon the top of the wall, 

 and being supplied with pieces of clay by an assistant below, 

 he elevates his arms and throws the mass forcibly down, and 

 then treads the pieces more firmly together with his feet. 



The layers are brought to the required batter, and smoothed 

 on the outside, by means of a flat cutting spade. The heat 

 and extreme dryness of the climate, soon render a wall of 

 this description hard and firm, and they last a very long time, 

 as rain seldom falls. Most Persian villages are surrounded 

 by high walls of this kind, having flanking towers at eveiy 

 angle, and a rude ditch in front, from which the materials 

 were excavated, and even the fortifications of the principal 

 cities are constructed of the same material. Almost all the 

 houses are also built in this way, and it is only when room is 

 valuable that thin partition-walls are erected of bricks. 



Brick- Building. — Of this there are two kinds, — buildingwith 

 sun-dried brick, and with kiln-dried brick ; the method of build- 

 ing, however, is much the same for both. The mortar is gene- 

 rally clay, mixed with chopped straw, and sometimes contain- 



