PREFACE 



The problem of developing and establishing accu- 

 rate standards and procedures for calibration <>l 

 underwater sound equipment required the attention 

 of many laboratories operating under contract with 

 Division (i, NDRC. Although most of this work was 

 done originally by the Bell Telephone Laboratories 

 and later by the Underwater Sound Reference Labo- 

 ratories of Columbia University, a number of other 

 organizations contributed to the results summarized 

 in this volume. In view of the wide scope of this field, 

 however, it was not possible in the limited time 

 allotted for the preparation of this volume to include 

 a complete treatment of all of the numerous contri- 

 butions. The principal reports covering this comple- 

 mentary work have been included in the bibliog- 

 raphy and are preserved in the form of microfilm 

 records. 



In the preparation of this volume, the emphasis 

 has been placed on the experience gained by Divi- 

 sion 6 laboratories in developing testing methods and 

 apparatus and in carrying through an extended pro- 

 gram of precision measurements on underwater 

 acoustic devices. The basic principles of these meas- 

 urements are developed and systematized in close 

 coordination with a description of the measuring and 

 calibrating facilities of the test stations at Mountain 

 Lakes, New Jersey and Orlando, Florida. It is be- 

 lieved that these descriptions are sufficiently complete 

 to be of material service to other groups in setting up 

 and maintaining similar equipment. 



As the responsibility lor preparing this volume was 

 assigned by the chief of Division 6 to the staff of the 

 Underwater Sound Reference Laboratories, the 

 greater part of the material included is, of necessity, 

 drawn from the experience of this group. The entire 

 stalls of the Mountain Lakes and Orlando stations, as 

 well as the stall of the New York office, have collabo- 

 rated in all phases ol the task of collecting and pre- 

 paring the data upon which the present work depends. 

 This group included: Edwin L. Carstensen, E. Dietze, 

 W. Richard Elliott. Leslie L. Foldy, Frank H. Gra- 

 ham, Earle C. Gregg, Jr., Erhard Hartmann, Norma 

 Hartmann, F. William Hoffman, Paul F. Joly, Joseph 

 15. Keller, Martin |. Klein, L. Pauline Leighton, 

 Lucille Northrop, Henry Primakoff, Edward S. Rog- 

 ers, Robert S. Shankland, Erwin F. Shrader, D. Ber- 

 nard Simmons, Richard J. Tillman. 



Acknowledgement should also be made of contri- 

 butions by Division 6 laboratories at the Massachu- 

 setts Institute of Technology, Harvard University, 

 University of California, and Columbia University. 

 In addition, valuable assistance was received from 

 the Brush Development Company, Submarine Signal 

 Company, the Radio Corporation of America, and 

 I lie service laboratories of both the United Slates and 

 British Navies. 



R. S. Shankland 



Director, Underwater Sound 



Reference Laboratories 



