512 



G. H. DREW. 



fathoms, but there was some stray on the wire, so that the true 

 depth was probably about 825 fathoms, as shown by the chart. The 

 bottom consisted of fine white calcareous ooze ; no remains of pteropods 

 were seen, but some globigerina shells were present. The following 

 temperatures were recorded : — 



Depth in fathoms, 

 Surface 



10 



50 

 100 

 200 



300 ... 



400 ... 



Bottom... 



U-37 

 14-27 



9-86 

 9-73 



4-17 

 4-13 



Samples down to a depth of 200 fathoms were diluted 1 in 100 

 with sterilized sea-water before plating. The following results were 

 obtained after 48 hours' growth : — 



The figures given represent the mean of the number of colonies 

 developing in the two plates that were made from each sample. 

 It is here apparent that the number of bacteria per 1 c.c. falls off 

 very rapidly between 200 and 300 fathoms. 



The third station was worked on May 23rd at a point 10 miles 



