204 THE SEA FLOOR 



record. Sometimes, however, the whole of the mud 

 would slip out of the tube while being hauled up. To 

 prevent this, valves and balls at the upper end of the 

 tube were used with varying success. In positions 

 where a typical Globigerina Ooze was expected, a 

 butterfly valve was generally inserted in the lower 

 end of the tube, and this arrangement was generally 

 successful in retaining some of the deposit. To place 

 three or four small tubes side by side, without valves, 

 has been found a good arrangement. Gravel and 

 small stones are the most difficult of all samples to 

 recover, and for these the snapper (Fig. 199, p. 282), 

 and the " Rendle tube" are the most successful. 

 During the " Michael Sars " Expedition (1910) a 

 heavy contrivance of Nansen's was successfully used 

 to bring up a section of the deposit, but this entailed 

 a stranded wire and a separate sounding operation. 



In the dredge and trawl large quantities of the 

 deposits were sometimes brought to the surface, and 

 a careful examination of these threw a great deal 

 of light on the samples procured by the sounding 

 machine. Large samples of mud, ooze, or clay, were 

 carefully passed through wire sieves (Fig. 158) with 

 different sized meshes, and these coarse and fine 

 " washings " were carefully preserved for future 

 examination. It has often been regretted that larger 

 samples procured in the dredge were not preserved 

 and brought home without being passed through 

 sieves. 



The samples of deep-sea deposits which are pro- 

 cured are best preserved by being at once placed in 

 wide-mouthed glass-stoppered bottles, and a small 

 quantity of methylated spirit can be with advantage 

 added, although this is not essential. Cork-stoppered 

 bottles and tubes can also be used. Spirit, added to 



