6i6 



C I V I L A R C H I T E C T U R E. 



. , 



- 



P.-cik. MI to it* rtviral and prrient state, reserving the Gothic 

 to the Utter end of this article. 



1'rerious to producing specimens of the different varia- 

 tion* of ttyle which have taken place in thr course of 

 the Utt 400 yean, we shall endeavour to discuss the 

 component part* of a building ; which being generally 

 applicable t we are unavoidably led to consider frequently 

 as connected both with ancieut and modern practice. 



FD: - Thii term is applied to the excava- 



:'.*ds in the ground for the base of a building. 

 Tl:e trenchei should be sunk till they arrive at firm soil 

 or -olid rock ; and in large buildings, the ground should 

 be further proved by digging pits, or boring to a consi- 

 derable depth. If the ground be rather soft or loose, 

 but tolerably firm, pieces of oak, termed sleepers, arc 

 laid across the trench, about two feet distant from each 

 other, their lengths being about two feet more than the 

 bottom of the intended wall, and the spaces between them 

 is filled with dry stone rubbish or iron cinders well ram- 

 med. Over these sleepers, planks are laid to a breadth 

 somewhat exceeding that of the masonry, and are spiked 

 to the ilccpcrs; a:;d this operation must be extended to all 

 the walls, external and internal, that the whole edifice 

 may have an equal bearing. If the ground be very soft 

 and loose, wooden piles must be driven to secure the 

 planking. They should be of a sufficient length to reach 

 th.e solid ground, and be driven as close together as prac- 

 ticable. Their thickness should vary from being about 

 one-sixth of their length in short piles, to one-twelfth in 

 long ones. Where the ground is generally firm, but ha- 

 ving some soft spaces, arches may be turned over the lat- 

 ter. When the superstructure is to stand on narrow piers, 

 inverted arches should be turned between ; if the ground 

 under these is loose, piles and planking must likewise be 

 used. When the foundations are upon slanting ground, 

 the trenches must have their bottoms cut in rectangular 

 steps. Forced earth is unfit for foundations, and can 

 icarcely be rendered fit by any precaution short of ma- 

 king a sufficient platform, connected with the original 

 unmoved ground. 



Besides the foregoing application of the term Founda- 

 tion, it also indicates the substructure, or bottom of a 

 wall, which consists of one or more offsets or steps on 

 each side of its perpendicular face?. These are denomi- 

 nated footings. The breadth of this substructure must 

 be proportioned to the weight of the superstructure, and 

 the nature of the ground. Where the texture of the 

 *oil appears to be tolerably equal and firm, and the mate- 

 rial* of similar specific gravity, the breadth will be as the 

 area of the vertical section passing through the line in 

 which it is measured. For example, suppose a wall 40 

 feet high and 2 feet thick to have a sufficient foundation 

 at the breadth of 3 feet, what should the breadth of the 

 foundation be, when the wall is 60 feet high and 2J feet 

 thick ? By taking the proportion 40 X 2 : 3 : : GO X 2f, 

 we shall have 5| feet. In stone walls, th Itajt breadth 

 added to that of the superstructure, is one foot. In 

 damp situations, charcoal, sand, tarred paper, and Park- 

 er's British cement, may all be used with advantage. 

 Of walla, WALLS IN GENERAL. A wall should be able to resist 

 a given force, acting upon it either with uniform pres- 

 sure over the whole surface, or pressing partially upon 

 certain portions. It should be capable of sustaining the 

 pressure of vaults or roof acting along a continued abut- 

 me,nt ; or upon point*, as groin vaulting ; also the power 

 ttfabe wina acting uniformly upon the whole surface ; 

 and all these are to be ascertained by calculations which 

 the properly qualified architect will be capable of mak- 



i - .-.. 1. 1 



.-,..!. 



ing. He may also be assisted by referring to the theory Prr tir e. 

 ofarches in the article BRIDGE. " p ~i ""' 



There arc many sorts of walls : We shall first insert Different 

 the substance of what has been said on the subject by " 

 Vitruvius and Palladio, and then explain the modes 

 practised in the present day. 



The wall which Vitruvius names uncertain, is one where 

 the stones are laid in their natural shape and dimensions, so 

 that the size and figure of the courses are various, as at A, p.. T , 

 (see Plate CLXXX1X. Fig. 1.) Perrault calls those in- rLXXXIX . 

 serted, when the stones are of a determined size, and pla- t, f _ i. 

 ced in a regular order like brick- work. In this sort of 

 work the stones should be longer and shorter alternate- 

 ly, or their position varied, so as to break joint, tic to- 

 gether, and render the whole firm and close. The Greeks 

 made their walls frequently in the mariner of brick walls, 

 with a hard stone, having the outer face of a square 

 form, that is, of equal depth and breadth, such as B, Fig. j-, . 

 2 ; or with stones of irregular size, as C, Fig. 3. The H ;; 

 third sort were termed involved, as D, Fig. 1, where the 

 stones were even in the front, but laid irregularly. Walls- 

 were termed cramped when the interior was composed of 

 rubble, or broken or pounded cement, and the ouuides 

 of squared stones tied together by iron, as at E, Fig. 4 ; 

 or where the squared outside stones were occasionally 

 connected by long stones that went through the whole 

 thickness of the wall, as at F, Fig. 4 ; and sometimes Fig. 4. 

 these etones went only about two thirds of the thickness, 

 having a stone overlapping it from the other side in the 

 next course. The term network, or reticiilutcd, was 

 applied to work, where the stones were square in their 

 outer faces, but laid in courses inclining to the horizon 

 at an angle of 45, as G, Fig. 5. This mode was much p;^ 5, 

 practised at Rome, but is not calculated to afford sta- 

 bility. 



The precepts of Palladio are as follow : Net or reti- 

 culated works (A, Fig. 6.) he condemns as being un- Fig. ft 

 stable ; but if it is to be used, he proposes to construct 

 buttresses at the angles BB, and place transversely or 

 longwise six courses of stones or bricks laid horizon- 

 tally at the bottom CC, and in the middle three, as 

 DD, wherever the net or reticulated work is raised six 

 feet. 



Brickwork, in walls of considerable magnitude, he di- 

 rects to be constructed as at EE, Fig. 7, the rubbish pjg. 7. 

 lying concealed in the middle as at FF. In the bottom 

 to have six courses of bricks of a larger size than ordi- 

 nary, then to build up about three feet in height with 

 the commor.-sized bricks, and upon these to bind the 

 wall again with three courses of the larger bricks. Spe- 

 cimens of this mode are found in the Pantheon and baths 

 of Dioclesian at Rome. 



A third sort of walls is composed of rongh pebbles 

 out of a river, or taken from a rock, and laid irregularly 

 in cement, as at I, Fig. 8. This should be bound by three pjg g, 

 courses of bricks at every two feet in height, as K. 

 This kind of work is seen in the walls of Turin in Pied- 

 mont. 



The fourth sort is termed uncertain, as L, Fig. 9 ; a Fig. D. 

 specimen of which remains at Prcneste, twenty miles from 

 Rome. 



The fifth mode is composed with squared btoncs, as 

 at M, Fig. 10. It is named f.scuilisoiiomim, and is to be ?> I(> 

 b.-in i.i the temple of Augustus at Rome. 



The sixth, as at Sirmion upon the lake of Gardi. 

 They are formed by making two sides of stakes and 

 planks, as N, Fig. 11, between which stones and mortar rig. II. 

 are throws in promiscuously j when these have set or con- 





