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The only magnetic instrumentation that is needed is an airborne or sea- 

 borne instrument capable of measuring the necessary three components required 

 to describe adequately the earth's magnetic field at a point. This instrument 

 would make it possible to observe the areal distribution of the earth's magnetic 

 field in detail for the first time. 



A new method known as the Carbon- 14 method of measuring some of the 

 ocean currents has evolved. The principle of the method is to measure the de- 

 cay of radioactive carbon in a water sample. The amount of decay is a measure 

 of the number of years since the water has been in contact with the atmosphere. 

 For the measuring purposes it is necessary to obtain a 300 gallon sample from 

 which a 12 gram sample of carbon can be extracted. The carbon is obtained by 

 processing the water sample with concentrated sulphuric acid, bubbling CO^- 

 free nitrogen through the sample to drive off the CO2 gas and collecting the CO2 

 in ascarite after passing the gas through a suitable drying agent. The ascarite 

 is sealed and returned to the counting laboratory where the remainder of the 

 processing and counting is completed (Kulp, 1952). 



Originally the 300 gallon samples were taken with rigid steel tanks about 

 4 ft. in diameter and 5 ft. tall with ports at both ends. Recently a sampler 

 about l| ft. in diameter and 12 ft. long has been developed. This sampler is 

 made of canvas so that the tube can be collapsed, and a single port at the top 

 end is provided. The sampler is sent down into the water collapsed. When re- 

 covery of the sampler is commenced, a propeller, which can only operate when 

 in upward motion, first releases the bag and about 30 seconds later releases the 

 port cover. At the surface, the water is pumped from the bag into a processing 

 tank on the deck of the ship. The processing, which formerly required four 

 hours, can now be completed in 10 to 15 minutes. Since the canvas samplers 

 are light and have small cross-sectional areas, multiple casts are completely 

 practical. 



Two water samples from about latitude 550N and close to the mid-Atlan- 

 tic ridge have given water ages of about 1700 years. Although more measure- 

 ments are required, these indicate that oceanic circulation is much slower than 

 most workers have believed. If the water is moving along the bottom, requir- 

 ing centuries to move from the poles to the equator, the heat flow through the 

 ocean floor must be negligible and the whole heat budget of the earth will re- 

 quire reconsideration. 



The only instrumentation improvement which appears desirable is a 

 pressure indicator to confirm the depth at which the port closure occurred. Al- 

 ternatively a technique for removing the carbon in situ would eliminate all ques- 

 tions of contamination and would greatly simplify the handling problems. 



Recordings of sounds from large charges fired in the Sofar channel have 

 revealed numerous topographic echoes in the Atlantic (Luskin, in press). About 

 20 echoes have been identified with known sea mounts, islands, or shore lines. 

 The echoes from shore lines arrive as a sequence of discrete echoes rather than 

 a long continuous echo. The position of a new sea mount about 350 miles from 

 Bermuda was forecast on the basis of its echoes, and a subsequent cruise con- 

 firmed its existence within about 5 miles of the predicted position. No echoes 

 of measurable amplitude have been found which do not conform to known obstruc- 

 tions. No instrumentation is required for this work which is not a normal com- 

 ponent of a Sofar station. For best results the explosion should occur at the 

 sound channel axis and should be of 50 lbs. or more of TNT. Such charges 

 can readily be made from standard charges utilizing Woods Hole detonators. 



