ing, the moisture of the mortar; and this, if used plentifully, will consequently exercise a greater cementing power; because from their containing a large portion of moisture, the wall will not, of course, dry so soon as otherwise; and as soon as the moisture is absorbed by the pores of the stones from the mortar, the lime, losing its power, leaves the sand, so that the stones no longer adhere to it, and in a short time the work becomes unsound. We may see this in several monuments about the city (Rome) which have been built of marble, or of stones squared externally, that is, on one face, but filled up with rubble run with mortar. Time in these has taken up the moisture of the mortar, and destroyed its efficacy by the porosity of the surface on which it acted. All cohesion is thus ruined, and the walls fall to decay. He who is desirous that this may not happen to his work should build his two-face walls two feet thick, either of red stone, or of bricks, or of common flint, binding them together with iron cramps run with lead, and duly preserving the middle space or cavity. The materials in this case not being thrown in at random, but the work well brought up on the beds, the upright joints properly arranged, and the face-walls, moreover, regularly tied together, they are not liable to bulge, nor be otherwise disfigured. In these respects one cannot refrain from admiring the walls of the Greeks. They make no use of soft stone in their buildings; when, however, they do not employ squared stones, they use either flint or hard stone, and, as though building with brick, they cross or break the upright joints, and thus produce the most durable work. There are two sorts of this species of work, one called isodomum (CC), the other pseudisodomum (DD). The first is so called, because in it all the courses are of an equal height; the latter received its name from the unequal heights of the courses. Both these methods make sound work; first, because the stones are hard and solid, and therefore unable to absorb the moisture of the mortar, which is thus preserved to the longest period; secondly, because the beds being smooth and level, the mortar does not escape; and the wall, moreover, bonded throughout its whole thickness, becomes eternal. There is still another method, which is called EμTλEKTOV (emplecton) (E), in use even among our country workmen. In this species the faces are wrought. The other stones are, without working, deposited in the cavity between the two faces, and bedded in mortar as the wall is carried up. But the workmen, for the sake of despatch, carry up these casing walls, and then tumble in the rubble between them, so that there are thus three distinct thicknesses, namely, the two sides or facings, and the filling in. The Greeks, however, pursue a different course, laying the stones flat, and breaking the vertical joints; neither do they fill in the middle at random, but, by means of bond stones, make the wall solid, and of one thickness or piece. They, moreover, cross the wall from one face to the other, with bond stones of a single piece, which they call diaTovoi (diatoni) (F), tending greatly to strengthen the work." (G) is supposed to show the solid masonry of a wall properly bonded in the courses. MASS. (Germ. Masse.) The quantity of matter whereof any body is composed. The mass of a body is directly as the product of its volume into its density. Multiplied into the constant force of gravity, the mass constitutes the weight; hence the mass of a body is properly estimated by its weight. MASTIC. (Gr. MаσTIKη, a species of gum.) A cement employed for plastering outside walls. It is used with a considerable portion of linseed oil, and sets hard in a few days. From this latter circumstance, and from its being fit for the reception of paint in a very short period, it is extremely useful in works where expedition is necessary, but it must be constantly painted; when the oil has dried out, it has proved to be worthless. Asphalte mixed with coal tar or limestone, ready for use in paving, is termed "mastic." MATERIALS. Things composed of matter, or possessing its fundamental properties. MATHEMATICS. (Gr. Maonois, learning.) The science which investigates the consequences logically deducible from any given or admitted relations between magnitude or numbers. It has usually been divided into two parts, pure and mixed. The first is that in which geometrical magnitude or numbers are the subjects of investigation; the last that in which the deductions so made are from relations obtained by observation and experiment from the phenomena of material nature. This is sometimes called physics, or physical science. Mathematics, as respects what is necessary for the architect, comprises ARITHMETIC, ALGEBRA, and GEOMETRY. MAUSOLEUM. A term used to denote a sepulchral building, and so cailed from a very celebrated one erected to the memory of Mausolus, king of Caria, by his wife Artemisia, about 353 B.C. From its extraordinary magnificence, it was in ancient times esteemed the seventh wonder of the world. Many statues and other portions of it are now in the British Museum. MEAN. In mathematics, that quantity which has an intermediate value between several others, formed according to any assigned law of succession. Thus, an arithmetical mean of several quantities is merely the average, found by dividing the sum of all the quantities by their number. A geometrical mean between two quantities, or a mean proportional, is the middle term of a duplicate ratio, or continued proportion of three terms; that is, that the first given term is to the quantity sought as that quantity is to the other given term. In arithmetic, it is the square root of the product of the two given terms. The harmonical mean is a number such that, the first and third terms being given, the first is to the third as the difference of the first and second is to the difference of the second and third. MEASURE. (Lat. Mensura.) In geometry, strictly a magnitude or quantity taken as a unit, by which other magnitudes or quantities are measured. It is defined by Euclid as that which, by repetition, becomes equal to the quantity measured. Thus, in arithmetic, the measure of a number is some other number which divides it without a remainder, though, perhaps, such a definition rather intimates the notion of aliquot parts. But that meaning on which this article is submitted is the unit or standard by which extension is to be measured. We have measures of length, of superficies, and of volume or capacity. But the two latter are always deducible from the former; whence it is only necessary to establish one unit, namely, a standard of length. The choice of such a standard, definite and invariable, though beset with many and great difficulties, modern science has accomplished. The rude measures of our ancestors, such as the foot, the cubit, the span, the fathom, the barleycorn, the hair's breadth, are not now to be mentioned in matters of science, much more precise standards having been found, and not susceptible of casual variation. Nature affords two or three elements, which, with the aid of science, may be made subservient to the acquisition of the knowledge required. The earth being a solid of revolution, its form and magnitude may be assumed to remain the same in all ages. If this be so, the distance between the pole and the equator may be taken as an invariable quantity; and any part, say a degree, which is a ninetieth part of it, will be constant, and furnish an unalterable standard of measure. So, again, the force of gravity at the earth's surface being constant at any given place, and nearly the same at places under the same parallel of latitude, and at the same height above the level of the sea, the length of a pendulum making the same number of oscillations in a day is constant at the same place, and may be determined on any assumed scale. Thus we have two elements, the length of a degree of the meridian, and the length of a pendulum beating seconds, which nature furnishes for the basis of a system of measures. Others have been suggested, such as the height through which a heavy body falls in a second of time, determined, like the length of the pendulum, by the force of gravity, or the perpendicular height through which a barometer must be raised till the mercurial column sinks a determinate part; for instance, one-thirtieth of its own length; but these are not so capable of accurately determining the standard as the terrestrial degree, or the length of the pendulum. In the English system of linear measures, the unit has been for many years the yard, which is subdivided into 3 feet, and each of those feet into 12 inches. Of the yard, the multiples are, the pole or perch, the furlong, and the mile; 5 yards being 1 pole, 40 poles being 1 furlong, and 8 furlongs 1 mile. The pole and furlong, however, are now much disused, distance being usually measured in miles and yards. The English pace is 13 yards = 5 feet. See PERCH and MILE. Under the word Foor will be found the length of that measure in the principal places of Europe. The following table exhibits the relations of the different denominations mentioned: The measures of superficies are the square yard, foot, inch, &c., as under : In which it will be seen that the multiples of the yard are the pole, rood, and acre. Very large surfaces, as of countries, are expressed in square miles. See MILE. The relations of square measure are given in the following table : The measures of solids are cubic yards, feet, and inches, 1728 cubic inches being equal to a cubic foot, and 27 cubic feet to one cubic yard. By the act of 1824, the standard measure for all sorts of liquids, corn, and other dry goods, is declared to be the Imperial gallon. According to the act in question, the imperial standard gallon contains ten pounds avoirdupois of distilled water, weighed in air at the temperature of 62° Fahrenheit's thermometer, the barometer being at 30 inches. The pound avoirdupois contains 7000 troy grains, and it is declared that a cubic inch of distilled water (temperature 62°, barometer 30 inches) weighs 252-458 grains. Hence the imperial gallon contains 277-274 cubic inches. The gallon is subdivided into quarts and pints, 2 pints being cne quart, and 4 quarts one gallon. Its multiples are the peck, which is 2 gallons, the bushel, which is 4 pecks, and the quarter, which is 8 bushels. The relations of measures of volume are given in the subjoined table: The old wine gallon contained 231 cubic inches, the old corn gallon 268-8 cubic inches, and the old ale gallon 282 cubic inches. Subjoined are a few of the principal ancient measures of France: 1 toise, French 6 French feet 1 foot, do. 1 inch, do. 1 line, = =12 French inches 12 French lines = do. 1 point, do. According to General Roy, an English fathom a French toise:: 1000: 1065-75. In the new French system the metre, which is the unit of linear measure, is the tenmillionth part of the quadrant of the meridian=3.2808992 English feet (but lately ascertained by Capt. Henry Kater, to be more correctly 3-280916 English feet); and, as its multiples and subdivisions are decimally arranged and named by prefixing Greek numerals, the following table exhibits each: The unit of superficial measure, in the French system, is the are, which is a surface of 10 metres each way, or 100 square metres. The centiare is 1 metre square. The are, therefore, is equal to 1076-4297 English square feet. 119.6033 The unit of measures of capacity, in the French system, is the litre, a vessel containing a cube of a tenth part of the metre, and equivalent to 0-22009668 British imperial gallon. Its multiples and subdivisions are as follow: The unit of solid measure, or the stere, is equal to 35·31658 English cubic feet; therefore, There is much uncertainty respecting the ancient measures; the tables before printed being the usually received notions are continued, but subjoined are some of the dimensions given in Dr. W. Smith's Dictionary of Antiquities: MECHANICAL CARPENTRY. That branch of carpentry which relates to the disposition of the timbers of a building in respect of their relative strength and the strains to which they are subjected. MECHANICAL POWERS. See MACHINE. MECHANICS. (Gr. Mnxarn, machine.) That science in natural philosophy treating of forces and powers, and their action on bodies, either directly or by the intervention of machinery. The theory of mechanics is founded on an axiom or principle, called the law of inertia, namely, that a body must remain for ever in a state of rest, or in a state of uniform or rectilineal motion, if undisturbed by the action of an external cause. Theoretical mechanics consists, therefore, of two parts:- Statics, which treats of the equilibrium of forces; and dynamics, or the science of accelerating or retarding forces, and the actions they produce. When the bodies under consideration are in a fluid state, these equilibria become respectively hydrostatics and hydrodynamics. MEDALLION. A square, or more properly, a circular, tablet, on which are embossed figures, busts, and the like. MEDIEVAL ARCHITECTURE. The architecture of England and the Continent during the Middle Ages. It is also chiefly called GOTHIC and POINTED. MEGALITHIC. A term which has lately been applied to those works usually called Celtic and Druidical. MEHRAB. A niche in a mosque of the Mahomedans which marks the direction of the Kebla or temple at Mecca, to which their religion directs them to bow their face in praying. MEMBER. (Lat.) Any part of an edifice; or any moulding in a collection of mouldings, as of those in a cornice, capital, base, &c. MENAGERIE. (Fr.) A building for the housing and preservation of rare and foreign animals. The ancient Romans of opulence usually had private menageries, a sort of small park attached to their villa, and in them various kinds of animals were placed. MENHIR. See MAENHIR. MENSA. The slab, top, or table of the altar of the Roman Catholic Church. MENSURATION. (Lat.) The science which teaches the method of estimating the magnitudes of lines, superficies, and bodies. MERIDIAN LINE. A line traced on the surface of the earth coinciding with the intersection of the meridian of the place with the sensible horizon. It is therefore a line which lies due north and south. In Italy these lines have been laid in large churches, as at Santa Maria del Fiore at Florence, the Duomo at Bologna, &c. They are traced on brass rods let into the pavement of the church, and marked with the signs, and otherwise graduated. A hole in the roof permits the sun's rays to fall on them at his culmination, thus marking noon as well as its height each day in the heavens. MERLON. The plain parts of an embattled parapet, between the crenelles or embrasures. MEROS. (Gr.) The plane face between the channels in a triglyph. See TRIGLYPH. MESAULE. (Gr.) Described by Vitruvius as itinera or passages; they were, however, smaller courts. Apollonius Rhodius, in describing the reception of the Argonauts at the palace of Eetes, conducts them first into the vestibule, then through the folding gates into the mesaula, which had thalami here and there, and a portico (abovσa) on every side. META. (Lat.) A mark or goal in the Roman circus to which the chariots, &c., ran. METAL. (Gr. Meraλλov.) A firm, heavy, and hard substance, opaque, fusible by fire, and concreting again when cold into a solid body such as it was before; generally malleable under the hammer, and of a bright glossy and glittering substance where newly cut or broken. The metals conduct electricity and heat, and have not been resolved into other forms of matter, so that they are regarded as simple or elementary substances. They also reflect, when polished, both light and heat. Modern chemists have carried the number of metals to over forty-two, only seven whereof were known to the ancients; namely,-1. Gold, whose symbol is thus marked; 2. Silver, D; 3. Iron, 8; 4. Copper,; 5. Mercury,; 6. Lead, 2; 7. Tin, 4. METATOME. (Gr. Mera, and Teμvw, cut.) The space or interval between two dentels. METOCHE. (Probably from MeTeXw, I divide.) In ancient architecture a term used by Vitruvius to denote the interval or space between the dentels of the Ionic, or triglyphs of the Doric order. Baldus observes that in an ancient MS. copy of that author, the word metatome is used instead of metoche. This made Daviler suspect that the common text of Vitruvius is corrupt, and that the word should not be metoche but metatome, as it were section. METOPA. (Gr. Mera, between, and Orŋ, a hole.) The square space in the frieze between the triglyphs of the Doric order: it is left either plain or decorated, according to the taste of the architect. In very ancient examples of this order the metopa was left quite open. Figs. 1414 and 1415 represent two sculptures from the Parthenon at Athens. METRE. The French unit of length (see MEASURE), from whence is derived their metrica system now followed by many other nations. |