In Scotland and Sweden, granite is made use of as a building material. It lies in large masses, generally se parated by gunpowder into moderate, though still large dimensions, which are again cut into suitable scantlings, by means of iron instruments called plugs and feathers. They are not only worked into plain square forms, but also mouldings of considerable delicacy, by means of pointed tools of different sizes and weights. At Aber deen, in Scotland, where excellent granite is produced, and the. working of it brought perhaps to the greatest pet fection, there are handsome porticos, consisting of co lumns, bases, caps, and entablatures, executed in gra nite with great nicety. In the middle of the city a public building, whose front is composed of a full Doric order, is wholly completed with this excellent material. There are two sorts of granite, the one grey and the other red ; the last being the hardest, is most difficult to work, con sequently the former is most frequently employed; it consists of feldspar, mica, and quartz. It is much em ployed for paving the carriage way of streets, and in the curbing of the flat side pavements ; also for piers and footpaths of bridges; and for facings and copings to quays and wharfs. At Aberdeen, it is employed in construct ing very extensive piers, for protecting the entrance of the harbour ; and in the Eddystone and Bell-Rock light houses, it composes the facings, where they are exposed to the action of the sea.
basalt, and schistus, are also used in rubble work. The former dressing freely with the hammer, in one direction, may readily be formed with good faces, but not being stratified, their beds are uncertain, and not easily improved by art ; the latter, that is schistus, is just the reverse, having naturally good beds, but being, in few instances, willing to dress square across the laminae : They are, indeed, where expellee is not an object, work ed to a face by the laborious operation of striking perpen dicularly with a wedge-mouthed hammer or stone axe : Both kinds arc laid, sometimes promiscuously, and at others in regular courses.
Limestone, where found regularly stratified, affords good building stone, and combines the advantages of both the former, having naturally good beds, and dress ing readily for a face.
A species of schistus stone affords a covering to roofs totally unknown to the ancients, and which, when good of its kind, and properly prepared and laid on, is both very effectual and beautiful : It is, in those northern cli mates, an object of sufficient importance to require to be treated more at length, than can, with propriety, be done in the present Section ; so that we must refer the reader to the word SLATE for farther information.
Bricks have, in England, become a material very ge nerally employed in constructing all kinds of buildings. The country is provided by nature with abundant sup plies of coal for burning bricks, which can, by means of the sea or numerous inland navigations, be, with great facility, conveyed to the large towns and populous dis tricts, where the demand has long been very great. Clay
of proper quality is usually found, either upon the spot or immediate vicinity ; a very limited number of work men, properly arranged, can manufacture a great num ber of bricks in a stated time ; these can readily be re moved to the place where they are to be employed ; being light to handle, and of a rectangular shape, the workmen lay them with facility and ease. By means of bricks, walls can be made much thinner than with almost any kind of stone, they are therefore cheaper, and occupy less space ; in forming doorways, windows, chimnies, apertures and angles of all kinds, the facility they afford is greater than that of any other durable material. A building, whose walls are made with bricks, dries soon, is free from damp ; and, if properly made, and thoroughly well burnt, bricks endure equal to most, and longer than many kinds of stone. The best modes of manufacturing them having already been so fully discussed in this work, under the word BRIG, it would be superfluous to repeat them.
Tiles have long been employed in England for cover ing the roofs of buildings situated in towns, and of farm houses and cottages in the country, but of late years the use of them has been much circumscribed by the exten sion of that of slates ; the particular mode of manufac turing and using them, will be found under the word Ti LE.
Respecting sand, the ancient and modern practice agrees nearly in all that need be said ; that which is of angular shape, hard texture, and perfectly free of earthy particles, is admitted to be best. The circumstances ne cessary to be attended to in employing it, have already been mentioned in the article BRIDGE.
Lime, as employed in mortar, has already been inves tigated and explained under the article BRIDGE. What regards the practical operations of quarrying and burn ing, will be found under the words Lim E, and LIMEKILN.
In regard to metals in modern times, the use of copper and bron:e has, in building purposes, been mostly aban doned. Brass has been continued in locks, pullics, sash windows, handles, and sliding plates, connected with bells, and sundry other purposes in fitting up the interior of apart ments. Iron has been applied to many purposes unthought of in former times. The improvement and general intro duction of cast iron bids fair to create a totally new school of architecture. It has already been occasionally employ ed in pillars, roofs, floors, chimnies, doors, and windows ; and the facility with which it is moulded into different shapes, will continue to extend its application. The before-mentioned purposes, to which it has already been applied, will be more particularly noticed in the discus sions of Practice in the different Branches of Architec ture ; and an investigation of the qualities of the mate rial itself, as well as the mode of procuring and manufac turing it, will form a separate and important head under the word IRON.