determine the positions on the curve which 

 represent the interpolated values at standard 

 depths, and enter the standard depth to the 

 right of the curve, indicating the position 

 with an arrow. 



4-6 BATHYTHERMOGRAPH TEMPERA- 

 TURE^DEPTH PROFILE.— A continuous 

 temperature against depth profile is plotted as 

 the bathythermograph observations are made. 

 The most convenient paper to use is 50-yard 

 rolls of graph paper scaled 10 x 10 to the inch. 

 Depth is represented on the vertical scale using 

 50 feet per inch. For routine observations 

 where speeds and courses are relatively con- 

 stant, the horizontal scale may be in units of 

 time, using one inch per hour. However, in 

 special cases and where frequent course and 

 speed changes are involved, as in current 

 studies, it is recommended that the horizontal 

 scale be in miles, using 10 miles per inch. 



The treated bathythermograph slide is viewed 

 against the proper grid. The slide number, 

 Greenwich mean time, and surface temperature 

 read to the nearest 0.1° F., are entered at the 

 top of the graph. Whenever more than one 

 bathythermograph is being used, record the 

 instrument serial number over the slide number. 

 A sample profile section is shown in figure 4-3. 

 The slide is then read; the depth of each one- 

 degree change is noted and plotted. As subse- 

 quent observations are entered on the graph, 

 points of equal temperature are connected. 

 Five-degree intervals are connected with solid 

 lines; other isotherms are dashed. The ship, 

 cruise number, and data should be noted every 

 24 hours at the top of the graph. Speed and 

 course changes also are recorded so that distor- 

 tions causing apparent anomalies will be 

 recognized. 



H. O. 607 



43 



