CHAUC . Soft earthy sandstone of marine origin, 

 composed chiefly of minute shells. It is white, 

 gray, or buff in color. Part of the ocean bed and 

 some shores are composed of chalk, notably the 

 "white cliffs of Dover", England. (17) 



CHANNEL. 



That part of a body of water deep 



enough for navigation through an area otherwise 

 not suitable. It is usually marked by a single 

 or double line of buoys and sometimes by ranges. 



2. The deepest part of a stream, bay, 

 or strait, through which the main current flows. 



3. A large strait, as the English Channel. 



4. A hollow bed through which water 

 does or may run. 



5. That part of a water aerodrome 

 designated for the take-off and landing of air- 

 craft in a given direction. 



6. A band of radio frequencies within 

 which a radio station must maintain its modulated 

 carrier frequency to prevent interference with 

 stations on adjacent channels. Also called fre- 

 quency channel. 



7. Any circuit over which telephone, 

 telegraph, or other signals may be sent by an 

 electric current. 



8. A lead (ice). (17) 



CHANNEL BUOY . A buoy marking a channel. (17) 



CHARACTERISTIC WAVE HEIGHT . See SIGNIFICANT WAVE 

 HEIGHT . 



CHARLES' LAW . States that at a constant pressure 

 the volume of a gas varies directly as the ab- 

 solute temperature. (37) 



CHARTED DEPTH . The vertical distance from the 

 tidal datum to the bottom. (17) 



"CHARYBDIS" . See GALOFARO . 



CHECKERED BUOY . A buoy painted with quadrilaterals 

 of alternate colors. (17) 



CHELICERA . One of the most anterior pair of appen- 

 dages on arachnids such as spiders, scorpions, and 

 the king crab. (19) 



CHSLIPED . The first thoracic appendage (pincer) of 

 a crayfish and related crustaceans. (19) 



CHEZY'S FORMULA . An empirica 

 velocity of a uniform flow of 

 tion of a stream. Th e formul 

 as follows: v = CVRS; in whic 

 velocity of flow; R, the hydr 

 section, which is obtained by 

 the section by its wetted per 

 of the water surface; and C, 

 ing upon the roughness of the 

 also upon the values of R and 

 derived its name from Antoine 

 brated French engineer of the 

 (14) 



1 formula for the 

 water through a sec- 

 a is usually written 

 h V denotes the 

 aulic radius of the 



dividing the area of 

 imeter; S, the slope 

 a coefficient depend- 

 wetted perimeter and 

 S. Chezy's formula 

 de Chezy, a cele-. 

 eighteenth century. 



CHILEAN CURRENT . See PERU CURRENT. 

 CHINFO. Chief of Information - U. S. Navy. 



CHIP LOG . A line marked at intervals (commonly 

 50 ft), and paid out over the stern of a moving 

 ship. By timing the intervals at which the markers 

 appear as the line is pulled out by a drag (the 

 "chip"), the ship's speed can be determined. The 

 wave length of ocean waves can be estimated by 

 noting the position of wave crests relative to the 

 markers . (24) 



CHIT IN . The nonprotein secreted in the exoskeleton 

 on arthopods and some other animals. Some plants, 

 such as blue-green algae, build their cell walls 

 of chitin instead of cellulose. (19,13) 



CHLORINITY . The number giving the chlorinity in 

 grams per kilogram of a sea-water sample is identi- 

 cal with the number giving the mass in grams of 

 "atomic weight silver" just necessary to precipi- 

 tate the halogens in 0.3285233 kilograms of sea- 

 water sample. 



CHLOROPHYLL . The green pigment, located in the 

 CHLOROPLASTS , which is necessary to the process of 

 photosynthesis. (18) 



CHLOROPLAST . A specialized body in the cytoplasm 

 which contains chlorophyll. (18) 



CHLOROSITY . Chlorosity is the property correspond- 

 ing to the chlorinity expressed as grams per 20°- 

 liter. Chlorosity is obtained by multiplying the 

 chlorinity of a water sample by its density at 20°. 

 (13) 



CHOP (WIND CHOP) . The short-crested waves that may 

 spring up quickly in a fairly moderate breeze, and 

 break easily at the crest. (10) 



CHOPPY SEA . Popularly, descriptive of short, rough 

 irregular wave motion on a sea surface. (24) 



CHORDATA. The phylum of animals with a notochord, 

 persistent or transient; includes the vertebrates, 

 amphioxus , tunicates, and tongue worm; the chor- 

 dates. (19) 



CHROMOTOGRAPHY . A chemical process of separating 

 closely related compounds by permitting a solution 

 of them to filter through an absorbent so that the 

 different compounds become absorbed in separate 

 colored layers comprising a chromatogram. 



CHROMATOPHORE . A pigment cell containing granules 

 or coloring material and responsible for color 

 markings on many animals (and plants). (19) 



CHROMOSOME . One of the small bodies ordinarily 

 definite in number of cells of a given species into 

 which the chromatin of a cell nucleus resolves it- 

 self previous to the mitotic division of the cell. 

 (Webster Dictionary definition) . 



CHUBASCO. A very violent wind and rain squall, 

 attended by thunder and vivid lightning, often 

 encountered during the rainy season along the west 

 coast of Central America. (17) 



CIAT . Commission Inter-American del Atun Tropical. 



CIC. Combat Information Center. 



CIERZO . See MISTRAL. 



CIESMM . Commission Internationale pour L'Explora- 

 tion de la Mediterranee. 



GIG . International Committee on Geophysics of 

 ICSU. 



CILIA . Microscopic hairlike processes attached to 

 a free cell surface; usually numerous, often ar- 

 ranged in rows, and capable of vibration. (19) 



CIM. Committee on International Geophysics (or 

 Geodesy) . 



CINCLANT. Commander-in Chief, Atlantic (USN/ 

 Allies). 



CINCLANTFLT . Commander in Chief, Atlantic Fleet 

 (USN) . 



CINCNELM. Commander in Chief, Naval Forces, 

 Eastern Atlantic and Mediterranean. 



CINCPAC. Commander in Chief, Pacific (USN/USA/ 

 USAF) . 



22 



