Figure C-11. Ejecting the BT slide. 



Figure C-12. Holding the BT slide. 



To remove the slide from the grid depress the 

 spring to loosen the slide from the grid mount. 



The trace scratched by the stylus is a temper- 

 ature-depth record. Each point on the trace rep- 

 resents a value of temperatui'c and depth which 

 can be read off the appropriate line of the grid. 

 The lines on the grid are established by actual 



Figure C-13. Labeling the BT slide. 



test of the instrument. Each BT has its own 

 grid for converting the stylus trace to tempera- 

 ture and depth readings. These grids are not 

 interchangeable between instrvmients. Serial 

 numbers of both grid and BT must agree. The 

 surface temperature is read from the BT slide 

 by noting the temperature of the point at which 

 the trace starts downward from the surface. 

 Temperatures should be read to tenths of a 

 degree and depth to within 10 feet (see inset of 

 fig. C-6). 



C-7 Storing and Shipping BT Slides.— After 



the BT slide has been read, place it in the plas- 

 tic storage box. Do not dip slide in lacquer. 



Whenever a full box of slides is accumulated 

 during the course of a survey, it should be packed 

 securely and shipped to the National Oceano- 

 graphic Data Center (NODC). To protect your 

 slides so that NODC has the necessary infor- 

 mation to process them, proceed as follows: 



1. Replace slides in issue box. 



2. Put no material between slides. 



3. Pad top of slides (use issue pad) before re- 

 placing cover. 



Figure C~U. BT grid. 



C-7 



