a. Cruise number 



b. Date the slides and log sheets vere received at the 

 Hydrographic Office 



c. number of slides received 



d. Number of log sheets received 



e. The microfilm reel number on vhlch the cruise Is 

 photographed 



f . The final number of usable prints 



g. The total number of prints distributed 

 h. Any pertinent remarks 



A file is maintained for all reports and other correspondence 

 received from and transmitted to each observing ship. 



A master file of bathythermograph grids (fig. 2) has been set up 

 in -which nearly li»-,000 grids have been sorted, filed, and indexed 

 according to instrument model numbers and serial numbers. 



?. Checking and Coding the Log Sheets and Slides 



The log sheets are checked for correctness of position 

 quadrants and associated meteorological data. Those observations 

 that have been Incorrectly coded are receded. In the photographic 

 process used, the log sheet is photographed with the slide and grid. 

 It has been fovtnd that the usual method of making red pencil corrections 

 directly above the original data is confusing and difficult to read on 

 the b athy thermograms . Therefore, a method is used in •vdilch the correc- 

 tions are made on a corresponding log sheet column. The columns are 

 then cut into strips and attached over the original data by means of 

 rubber cement. Thus, the original data are preserved and the strip 

 can be removed if desired. 



The slides are ahecked against the log sheets and, vhere 

 required, corrections are made for slide numbers, times, dates, and BT 

 instrument numbers. Cruise numbers are not added to the slides as they 

 appear on the log sheet heading strip at the top of each bathythermogram. 



Slides that are fogged are placed in a defogging box con- 

 taining cotton saturated vith lacquer thinner. Unlacquered slides are 

 sprayed with a light plastic coating such as Krylon or Spray-It. Broken 

 slides are carefully edge -cemented vith Duco cement. 



3. Hiotographing the Slides and Log Sheets 



The N. R. L. recorder-camera (fig. 3) consists of a projector 

 system in which the BT slide and grid are inserted and projected onto 

 an opal-glass screen. The projected image is then photographed together 

 with the log sheet information which appears directly above the screen. 

 The Intensity of the light which reaches the screen through the slide 

 and grid is Indicated on a microammeter that is wired to three photo- 

 electric cells placed in front of the lower portion of the screen. A 

 variac, controls the intensity of the projector lig^t. 



