CORER 



1. Reef; 2. Lagoon; 



CORAL REEF 

 3. Islond 



4, Islet; 5. Logoon channel 



(MSA, JAPAN. 19521 



core catcher in place. It has a sharpened rim 

 for penetrating the bottom and is attached with 

 several steel bolts. 



corer — A hollow tube that is driven into the ocean 

 floor for the purpose of collecting a bottom sedi- 

 ment sample. 



core retainer — See core catcher. 



core sample — A sample of rock, soil, snow, or ice 

 obtained by driving a hollow tube into the me- 

 dium and withdrawing it with its contained sam- 

 ple or core. In general, the aim of core sam- 

 pling is to obtain a specimen in its undisturbed 

 natural state for subsequent analysis. (5) 



coriolis force — An apparent force on moving par- 

 ticles resulting from the earth's rotation. It 

 causes the moving particles to be deflected to the 

 right of motion in the Northern Hemisphere and 

 to the left in the Southern Hemisphere; the 

 force is proportional to the speed and latitude of 

 the moving particle and cannot change the speed 

 of the particle. 



corona discharge — A luminous and often audible, 

 electric discharge that is intermediate in nature 

 between a spark discharge and a point discharge. 

 It occurs from objects, especially pointed ones, 

 when the electric field strength near their sur- 

 face attains a value near 1,000 volts per centi- 

 meter. 



corposant — See St. Elmo's fire. 



corrasion — Mechanical erosion performed by 

 moving agents such as wear by glacial ice, wind, 

 running water, etc., but is generally restricted 

 to basal rather than lateral excavation. 



corrected establishment — The mean high water 

 interval for all stages of the tide. 



correction for datum — A conversion factor used 

 in the prediction of tides to resolve the difference 

 between the chart datums of the reference sta- 

 tion. 



corrosion — The gradual deterioration of material 

 by chemical processes, such as oxidation or at- 

 tack by acids ; if caused by an atmospheric ef- 

 fect, a form of weathering. (5) 



cosine collector — In underwater optics a light 

 collector which accepts radiant flux in accord- 

 ance with the cosin law. ( 8 ) 



cosmic rays — Radiation that has its ultimate ori- 

 gin outside of the earth's atmosphere, that is 

 capable of producing ionizing events in passing 

 through the air or other matter, and that in- 

 cludes constituents capable of penetrating many 

 feet of material such as rock. The primary cos- 

 mic rays probably consist of atomic nuclei, 

 mainly protons, some of which may have ener- 

 gies of the order of 10" to 10^= electron volts. 

 Secondary cosmic rays are produced when the 

 primary rays interact with nuclei and electrons, 

 for example, in the earth's atmosphere; they 

 consist mainly of mesons, protons, neutrons, 

 electrons, and photons that have less energy 

 than the primary rays. Practically all of the 

 primary cosmic rays are absorbed in the upper 

 atmosphere, and almost all cosmic radiation 

 observed at the earth's surface is of the second- 

 ary type. (41) 



cosmic sediment — Particles of extraterrestrial 

 origin identified in deep sea sediments as black 

 magnetic spherules. (2) 



cosmogenic radioisotopes — Those radioisotopes 

 produced in the earth's gaseous envelope 

 through the action of cosmic radiation. Exam- 

 ples of such radioisotopes include Carbon", Trit- 

 ium, Beryllium', and Beryllimn". 



cospectrum — 1. The spectral decomposition of the 

 in-phase components of the covariance of two 

 functions of time. 



2. The real part of the cross spectrum of two 

 functions. (5) 



cotidal chart — A chart of cotidal lines that show 

 approximate locations of high water at hourly 

 intervals measured from a reference meridian, 

 usually Greenwich. 



cotidal hour — The average interval expressed in 

 solar or lunar hours between the moon's passage 

 over the meridian of Greenwich and the follow- 

 ing high water at a specified place. (5) {See 

 figure for cotidal chart.) 



cotidal line — A line on a chart passing through all 

 points where high water occurs at the same time. 



40 



