« ПретходнаНастави »
great importance; because, it afforded for building an universal material, as durable as stone, without the expense of carriage, and often with less labour than was required to dig and fashion the stone.
The best London bricks are made of clay, sand, and ashes; and are nine inches long, four and a half broad, and two inches and a half thick.
Obs. Hence in laying bricks, two in breadth, with the interstices for mortar, are equal to one in length, and the requisite crosses and ties may then be made without inequalities in the wall.
103. The first cement for walls, was either mud or clay ; but, in due time, experiment led to the preference of a mixture of lime, sand and water; to which, for plastering, the hair of oxen is now added. Trees presented the next building material, for beams, and boards in floors.
Obs. Lime is a stone deprived of its carbonic acid or fixed air by fire; by mixing it with sand or ashes, containing fixed air, you restore the line to stone again in a short time. Hence the composition of mortar.
With bricks and mortar, therefore, well laid by a bricklayer ; with wood well put together with nails, by a carpenter; the dwellings of the whole civilized world are now made.
Obs. Cast iron for many purposes, to which timber was usually applied, bas lately been used to great advantage.
104. Simply as is the contrivance of chimnies to carry off smoke, they are yet a recent invention; and, in building, were unknown till within the last five hundred years : down to that period, the smoke escaped through a hole in the roof of the house.
A middle contrivance, between a hole in the roof, and a close fire-place, was the open chimney against the wall; which we yet see in many old farm houses; and the family sit under the hole that carries off the smoke.
105. The means of letting in the light, and keeping out the cold, is also a recent invention. Anciently,
holes for light were made with wooden shutters, to open by day, and to close at night.
Various were the contrivances to let in light; and, at the same time, to keep out cold. Bladders, horn, and membraneous substances of animals and fish, were used for this purpose, in the houses of the great; but all these gave way to the fine invention of glass.
106. That useful material was discovered by accident: some Phænician carriers of soda, a few years before Christ, happening to light their fire between some of their lumps of this mineral, it melted, and mixing with the sand, produced glass. Soda and sand, or flints, melted together, continue to be the materials of which glass is made to this day.
Obs. The manufactory of glass was long confined to Phoenicia ; but so little improvement was made in it, that Nero gave 60,0001. for two glass cups that had handles. It was first applied to windows about the year 300; but did not get into general use till about 1000.
2. A glass manufactory is a proper object to gratify the curiosity of young persons. Flint, or purified stony sand, called silex, is mixed with pure soda, and exposed to a moderate heat, producing, what is called the frit ; this is then put into moderate-sized vessels, and exposed to a violent heat, till melted; and, on cooling a little, it becomes a kind of hot paste, which may be worked and moulded to any shape: the ingenuity and expertness of the workmen, in so moulding and shaping it into various vessels, is highly amusing.
107. Tiles for the roofs of houses are made of clay, in the manner of bricks. Slates dug from quarries are also used for the same purpose. In country places, where the earliest practices are still continued, roofs are thatched with straw: these will keep out the wet and cold, but generate a musty smell.
Paints, consisting of the oxides of metals, and of certain coloured earths, or natural oxides, mixed with oil, at once serve to preserve wood, and to purify and beautify the inside of houses.
VI. Of Architecture. 108. After the art of building had attained what was useful and necessary; luxury would aim at ornament :-an ingenious carpenter would become a carver; and an ingenious stone-mason, a sculptor.
The pillars which supported the work, would not be allowed to be quite plain ; but would be cut or carved in ornaments, at the head and base; and other parts of the room, or structure, would be made to correspond. Hence, arose what are called, the five orders of Architecture.
109. The five orders of architecture were successively invented in ancient Greece and Italy; and are called the TUSCAN, the DORIC, the IONIC, the CORINTHIAN, and the COMPOSITE ; they are to be found in all the principal buildings of the Christian world.
110 The Saxons, also, had a simple style of architecture; distinguished by semicircular arches and massive plain columns; these are still found in many of our oldest buildings.
The Normans, too, invented a beautiful style of architecture, called the Gothic, distinguished by its lightness and profuse ornaments; by its pointed arches, and by its pillars, carved to imitate several conjoined.
The gothic architecture is found in all our old cathedrals; and is often elegantly adopted in private dwelliugs.
obs. I. As more effectual means, than any verbal descrip. tion of conveying a knowledge of the several species of architecture, diagrams of the characters of: ach are given below; and to fix them in his recollection, e pupil should trace or copy them.
2. The Hindoos, Egyptians, Chinese, and Moors, have likewise their own seperate styles of ornamental building : r.othing can be more grand, harmonious, and picturesque, than each of these, in the splendid specimens which are to be seen in their several countries. In England, the Pagoda in Kew Gardens, is a pleasing specimen of Chinese architecture ; but we seem, in general, to prefer the five orders; to the Gothic.
VII. The Art of Clothing. 111. Most animals are provided with a coat of hair or wool for covering; but man seems to have been left naked, and, in many respects, destitute ; apparently to serve as a stimulus to his industry and invention.
Man seems, as to his own wants and powers, to have been formed to equalize climates and conquer the elements. His superb edifices, his control of fire and water, his application of light in the night, and his various clothing, distinguish his superior intellect.
112. In all climates, clothing is not alike necessary: between the tropics it is little required, except for ornament; but, in the temperate and frigid zones, man could scarcely subsist without some covering.
Holy Writ tells us, that the first clothing of Adam and Eve was the leaves of fig trees, sewn, perhaps, to gether; and, even at this day, our manufactures of clothing are derived, chiefly, from the fibres of the vegetable kingdom.
113. The skins of animals were doubtless the first