KEYNOTE ADDRESS 



TRANSDUCERS FOR OCEANIC RESEARCH--A WIDE SCOPE 



T. R. FOLSOM 

 Scripps Institution of Oceanography 

 La Jolla, California 



From its title, this Symposium might appear to 

 be just one more technical discussion of a highly- 

 specialized matter. However, this should not he 

 inferred; it has been my observation that people 

 who become involved with instruments, particu- 

 larly those for oceanographic application, fre- 

 quently are people having exceptionally wide 

 interests and much curiosity about other things. 

 I am deeply impressed with the very number of 

 things that become involved in the development of 

 new instruments, research instruments in general 

 and especially those intended for the sea. 



This breadth of scope seems to be borne out by- 

 history and is likely to remain true because of 

 the nature of the ocean, instruments and man him- 

 self. I will try to make clear what I mean by 

 tracing the evolution of one classical oceano- 

 graphic transducer system. I should like to show 

 how its development was coincident with and 

 closely related to a burst of interest in oceanic 

 exploration that rather abruptly influenced the 

 thinking of a large number of people. I believe 

 that somewhat similar circumstances and relation- 

 ships still prevail. 



It will be necessary, of course, to digress a 

 bit from a mere description of this single trans- 

 ducer. Transducers are only part of the whole 

 system; the rest must be taken into consideration 

 somehow and I mean this quite broadly. 



unpleasantness of the sort promoters and finan- 

 ciers are likely to pass off lightly as "technical 

 difficulties . " One was lack of thorough knowledge 

 of the equipment, especially the cables; another 

 was a vast ignorance of the oceanic areas that 

 had to be crossed. 



However, there is nothing more attractive than 

 success and land telegraphy certainly was a suc- 

 cess in a way easy to understand; consequently 

 ample money was made available for plunging wires 

 into the Atlantic whether or not wire or water 

 was understood. Indeed, there were some heroic 

 efforts thrown away at first but before long the 

 two land masses were joined. Electrical signals, 

 rather faster than packets, carried urgent infor- 

 mation across the oceans. 



Quite by accident, evidence concerning an 

 entirely different branch of human interest was 

 brought to light as a by-product of this engi- 

 neering feat. Through the press, almost every 

 intelligent person had become spectator to a 

 controversy boiling up over the evolution of 

 biological species and the cable grappling had 

 brought up experimental evidence supporting 

 Charles Darwin's views. It was now apparent 

 that the deep layers of the ocean should be a 

 likely place to find answers to this question so 

 greatly disturbing a large number of people. 



SETTING THE STAGE 



Somewhat over a hundred years ago a philosoph- 

 ical curiosity of Professor Joseph Henry was con- 

 verted into an extremely profitable invention by 

 the persistence of an art teacher named Samuel 

 Morse. This was the electromagnetic telegraph. 

 It was useful to almost everyone--and it made 

 money. Financing its spread was profitable 

 though risky. Even the speculation presently 

 associated with what is called "electronics" is 

 tame compared with the wild promotion of the 

 early telegraph systems . 



Atlantic Cables 



A web of wire soon spread over the continental 

 surfaces. These soon would have been inter- 

 continentally connected except for some 



THE CHALLENGER ADVENTURE 



In 1872 H.M.S. CHALLENGER was sent round the 

 world on what amounts to an official inquiry into 

 the third dimension of the ocean, and in particu- 

 lar into the species that live there. ^ This cer- 

 tainly was not the first oceanic survey but never 

 before had there been such an undertaking so 

 deliberate and systematic encompassing the whole 

 oceanic domain within its objective. 



The outcome was far reaching. It has been 

 accepted by later oceanographers as the prototype 

 oceanographic survey. Actually there was no 

 popular hero this time corresponding to the cable- 

 laying Cyrus Field. The CHALLENGER'S staff was 

 altered several times during the cruise and it 

 was because of this and the very mass of data 

 collected that publication was delayed for many 

 years. However, the scientific world for the 



Superior numbers refer to similarly numbered references at the end of this paper. 



