ABSTRACT 

 Since the beginning of the U. S. Navy's expanded bathy- 

 thermograph (BT) program, in 1941, the system of proces- 

 sing the data has changed very little. Log sheet data were 

 slowly and laboriously hand copied onto the bathythermo- 

 gram prints. Slides and log sheets were the only negatives. 

 In 1955 a new method was developed and put into operation 

 at the Hydrographic Office which places all the BT slide and 

 log sheet data onto 35-mm. motion picture film. Any number 

 of prints can be made, and the film can be used for automatic 

 transcription onto punch cards. 



