dense (dens)

and n. [= F. dense = Sp. Pg. It. den so, o, L. dens us, thick, close, set close, dense (opposed to rarus, thin, rare), Gr. da, = σύς, thick, dense Dasya.] I. a. 1. Having great or unusual consistenc consistency of elements or closene of parts; closely compacted or conglomerated; compact; close close; thick: as, a dense body; a dense cloud thick, dense, shaggy, hairy, rou rough: see or fog; a dense panicle of flowers. The cause of cold is the density of the body, for all dense bodies are colder than most other bodies. Bacon , Nat. Hist. This surrounding chaos was far from being solid: he resembles it to a dense though fluid atmosphere. Goldsmith, Animated Nature, I. 29. Burning of land, or burn-bating, is commonly called den shiring , that is Devons hiring or Denbighshiring, because most used, or first invented there. Mortimer, Husbandry. Mr. Beshop of Merton first brought into the south of Wilts hire the improvement by burn-beking, Den she ring, about 1639. Aubrey, Wilts. Royal Soc. MS., p. 287. ( Hall i well .) densimeter (den-sim'e-ter), n. [= Sp. dens i metro, metrum , a measure.] An apparatus for ascertaining the specific gravity or comparative density of a solid or liquid, as metals, gunpowder, or sea-water. That used for testing the density of gunpowder consists e entially of a ve el in which the gunpowder is weighed in connection with mercury. The ve el is first partially filled with mercury by creating a vacuum; it is then emptied and a known weight of powder is placed in it, and the mercury again added under the influence of the same vacuum, le being admitted, however, in consequence of the space occupied by the powder. A comparison of the amount of mercury admitted with the weight of the powder gives the specific gravity of the powder. The optical densimeter of Hilgard consists of a gla prism for holding salt water, and a collimating telescope for examining a ray of light pa ing through the water in the prism, the refraction of the light giving the density of the water by comparison with the known angle of refraction of distilled water or sea-water of a known density. Huch's densimeter is used for ascertaining the density of syrups while boiling. See salinometer, IMG:content-2378.png:[blocks in formation] sidad = Pg. densidade = It. dens ità, pact; closene of constituent parts; compactne , actual or relative. The density of the ether is greater in liquids and solids than in gases, and greater in gases than in vacuo. Tyndall, Light and Elect., p. 62. 2. The ma or amount of matter per unit of bulk. The ma is the ratio of the living force or double the energy of motion to the square of the velocity. Experiments made by Newton upon the effect of attaching ma es of different materials to pendulums have shown that the weights of bodies are precisely proportionate to their ma es; consequently, the density is measured by the specific gravity, or the weight of a unit bulk. The unit of density is generally taken as that of water at its temperature of maximum density (4° C., 39° F.) and under ordinary pre ure. Inasmuch as the gram was intended density to be, and within the limits of the probable error of the best observations actually is, the ma of one cubic centimeter of water under these conditions, it follows that the density as ordinarily expre ed is, as closely as po ible, the number of grams in one cubic centimeter of the particular kind of matter in question. The following table shows the density of several important substances: irid ium, 224; Platinumero, ray, 788, tin, 7.3; zinc, 7.2; the earth, 5.6; solution of iodides of mercury and pota ium, 3.2; diamond, 3.5; rock, about 2.7; aluminium, 2.6; sulphur, 2.0; magnesium, 1.7; the human body, 1.1; india-rubber, 1.0; alcohol, 0.8; ether, 0.7; lithium, 0.6; vapor of iodide of arsenic, 1.02; air, 0.0013; aqueous vapor, 0.0008; hydrogen, 0.00009. See 13.6; lead, 11.3; 10.5; copper, 8.9; 8.7; specific gravity, under gravity. The quantity of matter per unit of space is defined as the density of the ma filling that space. A. Daniell, Prin. of Physics, p. 194. The density of a body is measured by the number of units of ma in a unit of volume of the substance. Clerk Maxwell, Heat, p. 82. 3. In elect., the quantity of electricity per unit of volume at a point in space, or the quantity of electricity per unit of area at a point on a surface. The electric volume-density at a given point in space is the limiting ratio of the quantity of electricity within a sphere whose centre is the given point to the volume of the sphere, when its radius is diminished without limit. The electric density at a given point on a surface is the limiting ratio of the quantity of electricity within a sphere whose centre is the given point to the area of the surface contained within the sphere, when its radius is diminished without limit. Clerk Maxwell , Elect. and Mag., § 64. Gravimetric density of gunpowder, the weight of a measured quantity of gunpowder. It is expre ed by the weight, in ounces, of a cubic foot of the powder.- Magnetic density, the rate of distribution of lines of force in a magnetic field. The unit is the gau or one c. g. s. line per square centimeter.