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d. Recording methods. There are several mediums available for 

 recording data and the writer does not pretend to know thenn all. 

 However several are listed to indicate the range. 



1. Smoked glass has been used with great success on the bathy- 

 thermograph. Its advantages are high resolution, low fric- 

 tion and ability to withstand exposure to sea water. Its dis- 

 advantages of small size and inconvenience of smoke are real 

 but are often of minor importance. 



2. Waxed paper is commercially available, will give high resolu- 

 tion and in some cases will withstand immersion in water. 



It is usually available in rolls and can be used for long re- 

 cords. 



3. Pencil or ink on paper is very good if the record is large 

 enough. A conventional pencil or ink record on a paper or 

 plastic surface is convenient to work with. Ink suffers from 

 spilling if treated rough or smudging if the pen remains at 

 one place. Most ball point pens will not give satisfactory 

 service at slow writing speeds. A pencil requires a remark- 

 ably heavy pressure to give a satisfactory trace. 



4. A photographic record is nowhere near as inconvenient as 

 most people make out. The advent of the Polaroid Land 

 Camera can sometimes further alleviate the problem. Photo- 

 graphic recording has many competitors but is probably the 

 most versatile of all methods which give a visual record. 



5. Magnetic tape can be used for recording temperature data 

 with a wide range of coding schemes. 



TYPES OF INSTRUMENTS WHICH ARE IN THE DESIGN OR TESTNG STAGE 

 BUT WHICH ARE NOT GENERALLY AVAILABLE 



One of the difficulties in oceanography is that most instruments seem to 

 be in the design stage and are not generally available. It would appear imprac- 

 tical to more than mention some of the work which is going on as the individual 

 investigator is the only reliable source of information in the early stages of de- 

 velopment. 



a. Scripps has had considerable experience and luck with their "Thermi- 

 tow" which was designed to be towed near the surface of the water and 

 record on a commercial electrical recorder on deck. 



b. Devik of Norway has used an infra red pick-up to measure horizontal 

 differences in the surface temperature of lakes. 



c. Woods Hole Oceanographic Institution has been working on several 

 variations of a recording thermometer which will record for periods 

 of from a week to a year. 



d. Several laboratories have considered the problem of a thermometer 

 to be on the bottom of the ocean. 



e. Combined temperature and conductivity meters or salinity meters 

 have been built by the Bristol Company, WHOI, Chesapeake Bay Lab- 

 boratory and the Navy Electronics Laboratory. 



TEMPERATURE RECORDERS WHICH ARE NEEDED 



There will be no attempt to recommend which of these following ther- 

 mometers is the most important, because individual preference would vary 

 widely. It does, however, seem advisable to list a few important instruments 

 which still have to be made and become available. 



a. A Rapid Response BT For The Top Few Meters: When studying the 

 near surface problems, it would seem advisable to keep the recorders aboard 

 ship and have only the measuring elements in the water. The chief problems 



