502 riTE DEPTHS OF THE SEA. [chap. 



APPENDIX A. 



Summary of the Besults of the Examination of Samples of Sea- 

 water taken at the Surface and at various Depths. By Wm. 

 Lant Caepentek, B,A., B.Sc. 



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

 pure as possible, and free from any contamination caused by 

 matters derived 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. In two instances, however, the samples were taken 

 from abaft the paddles. 



Waters taken at depths heloxv the surface. — It was found 

 desirable to coat the brass Water-Bottles internally with 

 sealing-wax varnish, owing to the corrosive action of the sea- 

 water. The apparatus was then found to work perfectly satis- 

 factorily in all cases in which there was sufficient weight on the 

 sounding-line to which they were attached to keep the bottles 

 perpendicular, or nearly so. When, from the smallness of the 

 attached 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 suspension, 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 Avater from great depths being much more highly 



