chap, x.] CONTINUITY OF THE CHALK. 511 



These figures appear to show (1) that intermediate waters are 

 more free from organic contamination than either surface- or 

 bottom-waters, as might he expected from the comparative 

 absence of animal life in these waters ; (2) that the total absence 

 of organic matter is least frequent in bottom-waters, and most 

 frequent in intermediate waters, surface-waters occupying a 

 middle place in this respect; and (3) that there is not much 

 difference between bottom- and surface-waters, either in the total 

 quantity of organic contamination or in the relative propor- 

 tions of the " decomposed " and " easily decomposable " organic 

 matter. 



It may be worth notice that when the bottom- water from 

 great depths was muddy, tests made before and after filtration 

 showed that some of the organic matter was removed by this 

 operation. 



APPENDIX B. 



Results of the Analyses of Eight Samples of Sea-Water col- 

 lected during the Third Cruise of the ' Porciqrinc.' By Dr. 

 Frankland, F.E.S. 



Royal College of Chemistry, 

 November I5ih, 1869. 



Dear Dr. Carpenter, — Herewith I enclose results of analyses 

 of the samples of sea-water collected during your recent cruise 

 in the ' Porcupine.' 



I shall not attempt to draw any general conclusions from these 

 results ; your own intimate knowledge of the circumstances 

 under which the different samples were collected will enable you 

 to do this much better than I. 



There is, however, one point which is highly remarkable, and 

 to which I would draw your attention ; it is the large amount of 

 very highly nitrogenized organic matter contained in most of 



