WORKING UP MATERIAL 



491 



the diagram given in Fig. 18 from which may be estimated the depth at which the 

 recorder will run for different lengths of towing cable, 0-255 in. diameter up to 30 

 fathoms veered from the water-line. The depths were given in feet, but a scale of 

 metres is now introduced at the side. 



In the beginning a ball-bearing swivel was used between the machine and the 

 towing rope; but on the advice of H.M.S. 'Vernon' this was discarded as unnecessary 

 and liable to unlay the wire rope. 



METHOD OF WORKING UP MATERIAL COLLECTED 



At the end of a run the storage spool is taken out of the preservation tank of the 

 machine and may be kept in formalin until required for analysis. Examination of the 

 roll is carried out by unwinding it on a stage beneath a traversing microscope; both 

 have been specially designed for the purpose and are shown in Plate IV. Fig. 19 shows 



,, ,; ,3 ,* ,5 |6 ,7 ,a ,3 ,10 p.^-pl 



wwm7>Mmx \ ^mm/7/7 m \ 



Fig. 19. Diagram of the stage designed for examining the recorder rolls under a traversing microscope 



(see also Plate IV). For explanation see text. 



the examination stage in diagrammatic section. The storage spool is mounted at A, 

 and the two gauze bandings are led off round the rollers B, B', passed up and separated 

 to the right and left over the glass stages C and D. The gauze passing over the stage C 

 goes to the empty spool E and that passing over D goes round a series of rollers to pass 

 back under the whole frame to the spool at F. E and F are geared to the handle at G ; 

 when this is turned the two bandings are drawn apart so that when a section of the 

 graduated roll covers one stage the corresponding area of the plain gauze covers the 

 other. The plankton is now exposed on the upper surfaces of the two gauzes as they lie 



5-2 



