tended a cocktail party is aware of the fact that 

 as people gather and time progresses, the noise 

 level in the room where the party is being given 

 gets louder and louder until finally the room is 

 quite noisy indeed. By our usual notions of mask- 

 ing, it should be almost impossible to understand 

 any of the conversation, yet we all know that 

 people will gather together in groups of two or 

 more and carry on quite satisfactory conversations. 

 This means that a human being is able in some way 

 to focus his attention upon a desired source of 

 sound, and to some extent ignore other masking 

 sounds that may be present in the environment. 

 This particular effect has been called the "cock- 

 tail party effect." It may be added that the 

 phenomenon can show up in any number of situations, 

 not just at a cocktail party. (9) 



CODC . Canadian Oceanographic Data Center. 



COEC . Comite Central d^Oc^anographie et d^Etude 

 des Cotes. 



COEFFICIENT OF THERMAL EXPANSION . The relative in- 

 crease of the volume of a system (or substance) 

 with increasing temperature in an isobaric process. 

 In symbols this coefficient is 



V (ax) p- 



V 



where V is the volume, T the temperature, and p the 

 pressure, (24) 



COELENTERATES . A group of marine animals which 

 includes jellyfishes, corals and hydroids. (15) 



COLD-FRONT-LIKE SEA BREEZE (SEA BREEZE OF THE 

 SECOND KIND) . A SEA BREEZE which forms out over 

 the water, moves slowly toward the coast and then 

 moves inland quite suddenly. Often associated with 

 the passage of this type of sea breeze are showers, 

 a sharp wind shift from seaward to landward, and a 

 sudden drop in temperature. The leading edge of 

 such a sea breeze is sometimes called the sea-breeze 

 front. (Defant, F., in Compendium of Meteorology, 

 1951, p. 659). (24) 



COLD WALL . A term used to indicate the line or 

 surface along which two water masses of signifi- 

 cantly different temperature are in contact. The 

 amount of mixing along a cold wall may be very 

 small. The encounter between the warm waters of 

 the Gulf Stream and the cold waters of the Labora- 

 dor Current is an example. (12) 



COM . Commander. Prefix applied to abbreviations 

 of Naval commands only (e.g. DESLANT becomes 

 COMDESLANT) . 



COMASWFORPAC (ASDEFORPAC) . Commander Antisubmarine 

 Warfare Force, Pacific Fleet. Ford Island, Pearl 

 Harbor, Honolulu, Hawaii. 



COMASFORPAC/COMASWFORLANT . Commander Antisubmarine 

 Warfare Force, Pacific Fleet, Ford Island, Pearl 

 Harbor, Honolulu, Hawaii. Atlantic Force, U. S. 

 Naval Base, Norfolk, Virginia. 



COMEX . Comite d Exploitation des Oceans. 



COMMENSALISM . The association of two or more in- 

 dividuals of different species in which one kind 

 or more is benefited and the others are not harmed. 

 (19) 



COMOFTEVFOR . Commander Operational Test and 

 Evaluation Force. U. S. Naval Base, Norfolk, 

 Virginia. 



COMPASS . An instrument used in determining the 

 azimuth or direction of a body relative to the 

 meridian of a place. There are two kinds of com- 

 passes in use -- namely, the magnetic compass which 

 is actuated by the earth's magnetism and the gyro- 

 compass which is actuated by a rapidly spinning 

 rotor which tends to place its axis of rotation 

 parallel to the earth's axis of rotation. The first 

 is subject to certain errors known as the variation 

 and deviation of the compass and may also be af- 

 fected by -other local attractions. The gyrocompass 

 is free from these disturbances and indicates direc- 

 tion relative to the true meridian of the earth. 

 (14) 



COMPASS DIRECTION . Direction as indicated by a 

 compass without any allowances for compass error. 

 The direction indicated by a magnetic compass may 

 differ by a considerable amount from the true 

 direction referred to a meridian of the earth. (14) 



COMPASS ERROR . The amount by which a compass direc- 

 tion differs from the true direction. The error is 

 usually expressed in degrees and is marked plus (+) 

 or minus (-) according to whether the compass direc- 

 tion as read in degrees of azimuth is less or great- 

 er than the true azimuth. The error is to be ap- 

 plied according to sign to the compass reading to 

 obtain the true direction. The compass error com- 

 bines the effects of the deviation and variation 

 of the compass. (14) 



COMPASS POINTS . The four principal points of the 

 compass -- north, east, south, and west, are called 

 the cardinal points. Midway between the cardinal 

 points are the intercardinal points: northeast, 

 southeast, southwest, and northwest. Midway between 

 each cardinal and intercardinal point is a point 

 with a name formed by combining that of the cardi- 

 nal and intercardinal point, the former being 

 placed first, as north-northeast, east-northeast, 

 and so forth. Midway between the points already 

 indicated are points bearing the name of the near- 

 est cardinal or intercardinal point followed by the 

 word by and the name of the cardinal point in the 

 direction in which it lies, as north by east, north- 

 east by north, and so forth. In all, there are 32 

 points separated by intervals of 11 1/4°. Each of 

 these intervals is subdivided into quarter points. 

 (14) 



COMPENSATION DEPTH . The depth at which the light 

 intensity is just sufficient to bring about a bal- 

 ance between the oxygen produced by algae through 

 photosynthesis and that consumed by them through 

 respiration. (13) 



COMBER . (1) A deep water wave whose crest is pushed 

 forward by a strong wind, much larger than a white- 

 cap; (2) A long-period spilling breaker. (11) 



COMBINATION BUOY . A buoy having more than one 

 means of conveying intelligence, as a lighted sound 

 buoy. (17) 



COMB JELLIES . Common names for members of the 

 phylum Ctenophora; small jellyfish-like animals 

 which live in the surface layers of the ocean, 

 usually spheroidal and with comb plates. They are 

 common marine animals, often occurring in enormous 

 concentration; many species are strongly biolumines- 

 cent. (13) 



CONDUCTION . The transmission of heat directly from 

 hE)LECULE to molecule through a substance or through 

 materials which are in contact with each other. An 

 unprotected diver loses heat to the water around 

 him mainly by direct conduction through his skin. 

 (37) 



COMPLETE FREEZING. EARLIEST . The earliest reported 

 date when ten-tenths ice coverage was observed at 

 a specific location. 



COMPLETE FREEZING. LATEST . The latest reported 

 date when ten-tenths ice coverage was observed at 

 a specific location. 



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