ELASMOBRANCH 



Water at successive depths would drift in direc- 

 tions more to the right until at some depth it 

 would move in the direction opposite to the wind. 

 Velocity decreases with depth throughout the 

 spiral. The depth at which this reversal occurs 

 is of the order of 100 meters. The net water 

 transport is 90 degrees to the right of the direc- 

 tion of the wind in the Northern Hemisphere. 



elasmobranch — Any of numerous cartilaginous 

 fishlike vertebrates belonging to the subclass 

 Elasmobranchii, which includes the sharks, 

 skates, and rays. 



elbow — 1. A change in direction in the contour of 

 a submerged bank or shoal ; not a recognized 

 term by the ACUF. 



2. A sharp change in the direction of a chan- 

 nel. (30) 



electrical conductivity — A unit measure of elec- 

 trical conduction ; the facility with which a sub- 

 stance conducts electricity, as represented by the 

 current density per unit electrical-potential 

 gradient in the direction of flow. Electrical 

 conductivity is the reciprocal of electrical re- 

 sistivity and is expressed in units such as mhos 

 (reciprocal ohms) per centimeter. It is an in- 

 trinsic property of sea water and varies with 

 temperature, salinity, and pressure. 



electric log — A graphic recording of the various 

 electrical properties of a sediment or rock 

 through which a hole has been drilled. Obtained 

 by lowering electrodes into the hole. (2) 



electric ray — Any of the family (Torpedinidae) 

 of rays possessing a pair of electric organs ca- 

 pable of delivering a strong shock to humans if 

 handled. See ray. 



electroacoustic transducer — A transducer for 

 receiving waves from an electric system and de- 

 livering waves to an acoustic system, or vice 

 versa. (69) 



electrolyte — A substance which when dissolved 

 in a suitable liquid, such as water, dissociates into 

 ions and thus makes the liquid a conductor of 

 electricity. Sodium chloride {NaCl) is the most 

 common electrolyte in sea water. 



electromagnetic energy— »S'ee electromagnetic 

 radiation. 



electromagnetic radiation — (or electroTnagnetic 

 energy; often called, simply radiation) . Energy 

 propagated through space or through material 

 media in the form of an advancing disturbance 

 in electric and magnetic fields existing in space 

 or in the media. The term radiation, alone, is 

 used commonly for this type of energy, although 

 it actually has a broader meaning. ( 5 ) 



electromagnetic window — The concept that some 

 portion of the spectrum, whether radio waves, 

 ultraviolet rays, infrared (heat), radiant light 

 or electrical energy of some sort can be made 

 to penetrate the sea and exploit a "window" in 

 the opacity of the sea. 



electromechanical transducer — A transducer 

 for receiving waves from an electric system and 

 delivering waves to a mechanical system, or vice 

 versa. (69) 



electron — An elementary particle of rest mass 

 me equal to 9.107 X 10"^ grams and charge equal 

 to 4.802 X 10"^° statcoulombs. Its charge may 

 be either positive or negative. The positive elec- 

 tron is usually called a positron; the negative 

 electron is sometimes called the negatron. Most 

 frequently the term electron means negatron. 

 The negative electron is a constituent of all 

 atoms. In a neutral atom the number of elec- 

 trons is equal to the atomic number Z. 



electronic bathythermograph (BT) — A bathy- 

 thermograph which provides temperature read- 

 ings to 1,350 feet by using a thermistor and 

 pressure element to provide remote readout on 

 deck. 



electron-volt — (abbreviated ev). A unit of 

 energy equivalent to the amount of energy 

 gained by an electron in passing through a 

 potential diilerence of one volt. Larger multiple 

 units of the electron-volt are frequently used, 

 namely; Kev for thousand- or kilo-electron- 

 volts, Mev for million-electron-volts, and Bev 



EKMAN SPIRAL SHOWING DEPTH 

 OF FRICTIONAL RESISTANCE (D) 



for billion-electron-volts. 



lev =1.6X10-1" erg. 



(70) 



56 



