Directly above the screen, onto -which the Bllde and grid 

 are projected, is a long narrow slot the length and width of a single 

 line of the BT log sheet. Behind the slot is a roller system, similar 

 to that of a typewriter, which holds the log sheet in position for 

 photographing. Immediately above the slot are two channels into which 

 are inserted strips of paper on which are printed the log sheet headings 

 and the data column headings. 



A constant intensity lumiline-type lamp is used to illuminate 

 the log sheet information. The log sheet headings are filled out before 

 Insertion to show the assigned file or cruise number, the sheet number, 

 name of the ship, months year, time zone, and survey cruise name or 

 number if given. A space for writing in the key niimber on the finished 

 print is provided at the right-hand end of the strip. Facing this data 

 setup is mounted a Bell and Howell, Eyemc, 35-™™- motion picture camera. 

 It is electrically operated and automatically advances the film and 

 resets the shutter as each photograph is taken. The type of film used 

 is extremely fine grain panchromatic Micro-file. It is loaded on number 

 10 spools in 100-foot lengths. Approximately I5OO slides can be photo- 

 graphed on each spool. About ij-OO slides a day can be filmed. 



Briefly, the operating procedure is as follows: After loading 

 the camera with film, the log sheet heading strip is filled out to pro- 

 vide the same information as given on the log sheet. It is inserted 

 Into the top channel. The log sheet is inserted into the roller assembly 

 and the data line corresponding to the first slide to be photographed 

 is aligned to show in the slot. The data heading strip, showing the 

 proper geographic quadrants, is inserted into the center channel and 

 aligned with the log sheet coliimns. The BT grid is placed in a long 

 handled frame (fig. k) and inserted into a vertical stage. Fine posi- 

 tioning adjustments to the grid can be made both vertically and hori- 

 zontally by means of thiimbscrews . In a similar manner, the slide is 

 Inserted into a second stage Immediately behind the grid in such a manner 

 that the smoked surface of the slide and the emulsion surface of the 

 grid are nearly in contact. Parallax is thus reduced to a minimum. 

 The BT slide stage is also adjustable both vertically and horizontally. 

 The slide is adjusted horizontally to bring the trace at the 50-foot 

 level to the corrected "set-up temperature", by the method described 

 InH, 0. Pub. No. 6lk, Processing Oceanographic Data. It is adjusted 

 vertically so that the surface trace is aligned with the surface (zero) 

 depth line of the grid. 



These adjustments are viewed on a mirror by the operator. 

 The mirror is on hinges inside the recorder between the screen and 

 the camera. A lever raises the lid of the viewing port In the top 

 of the recorder casing and the mirror simultaneously. The lid of the 

 viewing port is opened and the mirror is raised to the proper angle 

 by a single motion of the lever. When the mirror is positioned, the 

 log sheet, data column headings, and the log sheet heading strips are 

 easily visible along with the projected image of the slide and grid. 

 After the necessary alignments have been made, the lid is closed and 

 the mirror lowered out of range of the camera by moving the lever forward. 



