1869.] on the Scientific Exploration of the Deep Sea. 481 



APPENDIX. 



I. — Summary of the Results of the Examination of Samples of Sea-water 

 taken at the Surface and at Various Depths. By Wm. Lant Car- 

 penter, B.A., B.Sc. 



Surface-waters. — Care was taken to obtain these samples as pure 

 as possible, and free from any contamination caused by matters de- 

 rived from the vessel, by dipping them up in clean vessels at a few inches 

 below the surface at or near the bow of the ship. Ia two instances, how- 

 ever, the samples were taken from abaft the paddles. 



Waters taken at depths below the surface. — It was found desirable to 

 coat the brass Water-Bottles (§ 19) internally with sealing-wax varnish, 

 owing to the corrosive action of the sea-water. The apparatus was then 

 found to work perfectly satisfactorily in all cases in which there was suffi- 

 cient weight on the Soundiug-line to which they were attached to keep the 

 bottles perpendicular, or nearly so. When, from the smallness of the at- 

 tached weight, or the roughness of the sea, the sounding-line was at an acute 

 angle with the general level of the sea-surface while it was being drawn up, 

 the results of the examination of water thus obtained rendered it highly 

 probable that some water at or near the surface had found its way into 

 the bottle, and that its contents were not to be relied on as coming from 

 the lowest depths. 



When Bottom-water was obtained from depths beyond 500 fathoms, 

 it was almost invariably charged with a quantity of very fine mud in sus- 

 pension, rendering it quite turbid. Many hours' standing was necessary 

 for the deposit of this ; but it was readily removed by filtration. In no 

 instance was there any evidence of water from great depths being much 

 more highly charged with dissolved gases than Surface-waters ; a consider- 

 able elevation of temperature being in all cases necessary for the evolution 

 of any dissolved gas. 



Mode of Examining Samples. — The samples of water thus taken were 

 examined with as little delay as possible, with a view to determine : — 



(1) The Specific Gravity of the water. 



(2) The total quantity of dissolved Gases contained in them, and the re- 



lative proportions of Oxygeu, Nitrogen, and Carbonic Acid. 



(3) The quantity of Oxygen necessary to oxidize the Organic matter 



contained in the water ; distinguishing between 



a, the decomposed organic matter, and 



b, the easily decomposable organic matter. 



(1) The Specific-Gravity determinations were made at a temperature as 

 near 60° Fahr. as possible, with delicate glass Hydrometers, so graduated 

 that the Specific gravity could be read off directly to the fourth decimal 

 place with ease. 



(2) The apparatus for the analysis of the Gases dissolved in the sea- 

 water was essentially that described by Prof. Miller in the second volume 



