Terminology

Lronardo, Vol. 8, p. 337-338. Pergamon Press 1975. printed in Great B r i t a i n TERMINOLOGY The terms defined below were selected from artists’ articles and Notes published in the previous issue of Leonardo. Each definition is followed by an indication of the volume and page number of Leonardo on which the term first appears. The terms were not found in the art dictionaries among the dictionaries listed in Leonardo 8, 67 (1975) or they are used in a new sense. Some are terms that have been carried over into the field of art from the natural and social sciences, from mathematics and from technology. Numbers in brackets, e.g. [lo, 151, refer to the dictionaries mentioned above. The definitions are not presumed to be unassailable. The Editors would, therefore, welcome the comments of readers on the definitions presented. 679. Absolute temperature, thermodynamic temperature (in physics)-A temperature measured on a scale based on absolute zero, which is the hypothetical lowest achievable temperature characterized by complete absence of heat. There are two common absolute temperature scales, one in degrees Kelvin (OK)and the other in degrees Rankine (OR). A temperature measured on the Centigrade scale (“C)can be converted to (“K) by the equation (“C)+273.16 = (K); on the Fahrenheit scale (“F), to (OR) by the equation (“F) + 459.69 = (“R). [14, 171 6 8 0 . Amplifier (in electronics)-A device that increases the strength of an electrical signal fed into it by obtaining power from a source other than the input signal. [14] 681. Chloromethane (in chemistry)-(cf. Methyl chloride, term 692) 6 8 2 . Cognition, cognitive processes (in psychology)Processes that include all the means whereby an individual represents anything to himself or uses these representations as a means of guiding his behaviour. (8, 225; [S. S. Stevens, ed., Handbook of Experimental Psychology (New York: John Wiley, 1951) p. 7361) 6 8 3 . Coir-A stiff coarse fibre from the outer husk of a coconut. (8, 194; [17]) 684. Continuous light source-A source (e.g. an incandescent lamp) that produces light characterized by a continuous spectrum. (8, 232) (cf. Incandescence, term 690; incandescent lamp, Terminology, Leonardo 1, 198 (1968) and spectrum, Terminology, Leonardo 7, 166 (1974)) 6 8 5 . Dry ice-Solid carbon dioxide. It is usually produced in the form of blocks generally for use as a refrigerant. It passes directly from the solid to the gaseous state at -785°C (-109°F). (8,222; [17]) 6 8 6 . Electrical relay (in electricity)-(cf. Relay, term 699) 687. Electron multiplier (in electronicsXd. Phoromultiplier , term 696) 688. Factor (in mathematics)-Any of the numbers (or symbols) that when multiplied together form a product. 1141 689. Gas discharge tube (in physics)-An evacuated enclosure containing a gas at low pressure that permits the passage of electricity through the gas if sufficient voltage is applied. The tube is usually provided with metal electrodes but discharge can occur without electrodes by induced voltage. (8, 232; [S. Handel, A Dictionary of Electronics, 3rd ed. (Harmondsworth, England: Penguin, 1972)l)(cf. Electrode, Terminology, Leonardo 4,288 (1971)) 690. Incandescence (in physics)-The emission of light from a body heated to a high temperature. 114, 171 691. Infinity (in mathematics)-That quantity that is greater than any assignable quantity. (8, 198; [14]) 692. Methyl chloride, chloromethane (in chemistry)-A colorless poisonous gas frequently used as a refrigerant. (8, 222; 1141) 693. Modular tapestry-A term denoting a type of tapestry made up of independent pieces that may be arranged in various ways, e.g. in a rectangular matrix, in a nonrectangular 2-dimensional pattern and in a 3dimensional array. (8, 191) (cf. Matrix, Terminology, Leonardo 1, 322 (1968)) 694. Nova (in astronomy)-A star that during an outburst ejects a small part of its material in the form of a gas cloud, causing the star to become 5,OOO to 10,OOO times more luminous thad it was before the outburst. (8, 222; [14]) 6%. Oscillator (in electronics)-A device with no rotating parts for converting direct current into alternating current. (8, 233; [141) 696. Photomultiplier, electron multiplier (in electronics)A photocell of high sensitivity for detecting very...