Page xii contents 



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Fig. 104. Schematic operating diagram of the Dorfsey Fathometer No. 1 474 



105. Magnetostrictive transceiver mounting 475 



106. Sounding with the Dorsey Fathometer No. 3 ^ 479 



107. Circuit diagram of Dorsey Fathometer No. 3 480 



108. Power supply rack of Dorsey Fathometer No. 3 482 



109. Magnetostrictive acoustic unit 497 



110. Intercircuit connections between 312 Fathometer and Dorsey Fathometer No. 3 506 



111. Location of the index adjustments, Dorsey Fathometer No. 3 515 



112. Circuit for verification of tuning-fork frequency by chronometer 521 



113. Separate acoustic units 525 



114. Curve of velocity corrections to echo soundings 534 



115. Velocity correction graph 536 



116. Facsimile of stamp used on fathograms 544 



117. Types of bottom relief shown vividly in fathograms of the 808 Fathometer _ . : 545 



118.. Various interesting fathograms of the 808 Fathometer 547 



119. Interesting fathograms of the 808 Fathometer 548 



120. Illustration of a fathogram on which notations have been properly made 550 



121. Sinusoidal sound wave 559 



122. Sound reflected from a rigid surface 561 



123. Multiple reflections in a bounded medium 562 



124. Total refraction of a sound wave 564 



125. Transmission of sound over great distances 569 



126. Path of sound through water of nonuniform velocity 570 



127. Path of sound through a layer with uniform velocity decrease from ;;i to ^2 571 



128. Path of sound caused by a velocity increasing uniformly with depth sufficient to 



refract the sound wave back toward the surface 572 



129. Annual cycle of temperature distribution in sea water near the surface 577 



130. Range of temperature curves in offshore ocean waters 578 



131. Graph to convert apparent specific gravity to salinity 585 



132. Velocity of sound determined from time intervals simultaneously measured to. 



three known stations 591 



133. Circuit diagram of Vincent sono-radio buoy 602 



134. Circuit diagram of East Coast sono-radio buoy 605 



135. Circuit for measuring and adjusting sono-radio buoy sensitivity 609 



136. Sono-radio buoy dummy tuning antenna 612 



137. Dorsey hydrophone 614 



138. Vincent sono-radio buoy hydrophone 617 



139. Bomb for deep detonation 621 



140. Circuit diagram of R.A.R. equipment for survey vessel 629 



141. Elapsed times obtained from a chronograph tape 651 



142. Facsimile of stamp used on chronograph tapes 655 



143. Temporary dog-ear for smooth sheet 660 



144. Polyconic projection of North America 668 



145. Referencing projection lines 669 



146. Construction of a polyconic projection 670 



147. Sheet limits for ruling-machine projections 672 



148. Change of datum of survey sheet — by numerical method 679 



149. Change of datum of survey sheet — by graphic method 680 



150. Construction of a polyconic projection on a completed survey sheet — for small- 



scale surveys 681 



151. Construction of a polyconic projection on a completed survey sheet — for large- 



scale surveys 682 



152. Control stations plotted by dms. and dps. on a distorted sheet 685 



153. Templates for triangulation station and buoy symbols 689 



154. Projection and control data for smooth sheet 691 



155. Shoreline shown on smooth sheet without obscuring positions of control stations 692 



156. Reduction of topography by method of squares 696 



