George Cruikshank's Mr. Bumble and Mrs. Corney, illustration for Oliver Twist by Charles Dickens, 1838.
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left the group. In the 1960s she released more than 20 albums in the U.S., including seven with Tito Puente. She became identified with salsa, a dance music that evolved from the musical experimentation of various Hispanic musicians with Caribbean sounds during the late 1960s. Cruz was the subject of a 1988 BBC documentary and appeared in films such as The Mambo Kings (1992).
Cruz, Sor Juana Ines de la (b. Nov. 12, 1651, San Miguel Nepantla, Viceroyalty of New Spain—d. April 17, 1695, Mexico City) Mexican poet, dramatist, scholar, nun, and an early feminist. Bom out of wedlock to a family of modest means, she was sent to relatives in Mexico City, where her great intelligence became known to the viceroy. She soon became a nun, remaining cloistered for the rest of her life. Sor Juana had one of the largest private libraries in the New World. Her most important works are the poem “Primero sueno” (1692; “Sor Juana’s Dream”), which recounts the soul’s quest for knowledge, and the “Respuesta” (1691; “The Answer”), her defense of women’s right to knowledge.
cryogenics \ l kri-o- , je-niks\ Study and use of low-temperature phenom¬ ena. The cryogenic temperature range is from -238°F (-150°C) to abso¬ lute zero. At low temperatures, matter has unusual properties. Substances that are naturally gases can be liquefied at low temperatures, and metals lose electrical resistance as they get colder (see superconductivity). Cryo¬ genics dates from 1877, when oxygen was first cooled to the point at which it became a liquid (-297°F, or -183°C); superconductivity was discovered in 1911. Applications of cryogenics include the storage and transport of liquefied gases, food preservation, cryosurgery, rocket fuels, and superconducting electromagnets.
crypt Subterranean chamber, usually under a church floor. The catacombs of the early Christians were known as cryptae, and when churches came to be built over the tombs of saints and martyrs, subterranean chapels were built around the actual tomb.
As early as the reign of Constantine I (ad 306-37), the crypt was consid¬ ered a normal part of a church. Later its size was increased to include the entire space beneath the choir or chancel; the crypt of Canterbury Cathedral is an elaborate under¬ ground church with its own apse.
Many secular medieval European buildings also had richly decorated crypts.
cryptographic key See cryptographic key
cryptography \krip-'ta-gra-fe\ Practice of the enciphering and deci¬ phering of messages in secret code in order to render them unintelligible to all but the intended receiver. Cryptography may also refer to the art of cryptanalysis, by which cryptographic codes are broken. Collectively, the science of secure and secret communications, involving both cryptogra¬ phy and cryptanalysis, is known as cryptology. The principles of cryp¬ tography are today applied to the encryption of fax, television, and computer network communications. In particular, the secure exchange of computer data is of great importance to banking, government, and com¬ mercial communications. See also data encryption.
cryptomonad V.krip-to-'mo-.nadN Any small organism with two fla¬ gella that is considered both a protozoan and an alga (see algae). Occur¬ ring in both fresh and salt water, cryptomonads contain pigments found only in red algae and blue-green algae (cyanobacteria). They sometimes live harmlessly within other organisms. Some species conduct photosyn¬ thesis. Others lack pigment-containing structures and eat organic matter, under certain conditions surviving on minerals alone.
crystal Any solid material whose atoms are arranged in a definite pattern and whose surface regularity reflects its internal symmetry. Each of a crys¬ tal’s millions of individual structural units (unit cells) contains all the sub¬ stance’s atoms, molecules, or ions in the same proportions as in its chemical formula (see formula weight). The cells are repeated in all direc¬ tions to form a geometric pattern, manifested by the number and orienta¬ tion of external planes (crystal faces). Crystals are classified into seven crystallographic systems based on their symmetry: isometric, trigonal, hexagonal, tetragonal, orthorhombic, monoclinic, and triclinic. Crystals
are generally formed when a liquid solidifies, a vapour becomes super¬ saturated (see saturation), or a liquid solution can no longer retain dis¬ solved material, which is then precipitated. Metals, alloys, minerals, and semiconductors are all crystalline, at least microscopically. (A noncrystal¬ line solid is called amorphous.) Under special conditions, a single crystal can grow to a substantial size; examples include gemstones and some arti¬ ficial crystals. Few crystals are perfect; defects affect the material’s elec¬ trical behaviour and may weaken or strengthen it. See also liquid crystal.
crystal lattice Three-dimensional configuration of points connected by lines used to describe the orderly arrangement of atoms in a crystal. Each point represents one or more atoms in the actual crystal. The lattice is divided into a number of identical blocks or cells that are repeated in all directions to form a geometric pattern. Lattices are classified according to their dominant symmetries: isometric, trigonal, hexagonal, tetragonal, orthorhombic, monoclinic, and triclinic. Compounds that exhibit a crystal- lattice structure include sodium chloride (table salt), cesium chloride, and boron nitride. See also solid-state physics.
Crystal Night See Kristallnacht
Crystal Palace Giant glass-and-iron exhibition hall in Hyde Park, Lon¬ don, that housed the Great Exhibition of 1851. It was taken down and rebuilt (1852-54) at Sydenham Hill, where it survived until its destruc¬ tion by fire in 1936. Designed by the greenhouse builder Sir Joseph Pax¬ ton (1801-1865), it was a remarkable assembly of prefabricated parts. Its intricate network of slender iron rods sustaining walls of clear glass estab¬ lished an architectural standard for later international exhibitions, like¬ wise housed in glass conservatories.
The Crystal Palace at Sydenham Hill, London. It was designed by Sir Joseph Paxton for the Great Exhibition of 1851 and rebuilt in 1852-54 at Sydenham Hill but was destroyed in 1936.
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crystalline rock Any rock composed entirely of crystallized minerals without glassy matter (matter without visible crystals). Intrusive igneous rocks (see intrusive rock) are nearly always crystalline; extrusive igneous rocks (see extrusive rock) may be partly to entirely glassy. Metamorphic rocks are also always completely crystalline and are termed crystalline schists or gneisses. Sedimentary rocks can also be crystalline, such as crys¬ talline limestones that precipitate directly from solution; the term is not generally applied to clastic sediments (made of fragments of preexisting rock), even though they are formed largely from the accumulation of crystalline materials.
crystallography \,kris-t3-'lag-r3-fe\ Branch of science that deals with discerning the arrangement and bonding of atoms in crystalline solids and with the geometric structure of crystal lattices. Classically, the optical prop¬ erties of crystals were of value in mineralogy and chemistry for the iden¬ tification of substances. Modern crystallography is largely based on the analysis of the diffraction of X-rays by crystals acting as optical gratings. Using X-ray crystallography, chemists are able to determine the internal structures and bonding arrangements of minerals and molecules, including the structures of large complex molecules such as proteins and DNA.