( 399 ) 



Quantity of Saline Matter in Deep and Surface Sea-Water, ob- 

 tained in Lat. 0° 33' N., and Long. 8" 16' E. ; also Result 

 of three experiments on the Temperature of the Sea at great 

 depths ; and state of the Barometer and Thermometer during 

 a gale of Wind off the Cape of Good Hope. Communicated 

 by Captain Robert Wauchope, R. N. 



My Dear Siii, — Agreeable with your wish, I beg to send 

 you, for insertion in your valuable Journal, a copy of Mr 

 Kemp^s examination of deep and surface water, which I ob- 

 tained when in command of H. M. ship Thalia, in October 

 1836, in Lat. 0° 33' N., Long. 8^ 16' E. The deep sea water 

 was taken from the depth of 65S fathoms ; it was brought up 

 from that depth by means of an instrument I have frequently 

 made use of for this purpose, consisting of a series of cases, one 

 within the other, having valves opening up so as to allow the 

 water to pass through on descending, but which closes on 

 hauling the instrument up. The thermometer was enclosed 

 in a glass tube in the centre of it. 



Temperature of surface water by Fahr. . . . 78| 



Do. of water from the depth of 653 fathoms, 43 



35f 



During this experiment there was no current, and when all 

 the rope was veered out, it was nearly perpendicular, not being 

 distant from the ship more than six fathoms. 



Mr Kemp writes : — " I have examined the two specimens 

 of sea-water marked ' deep and surface waters,' and find the 

 deep water to contain more saline matter than the surface wa- 

 ter, being about 4J per cent., the water at the surface having 

 about 3 per cent. It contains also sulphate and a small quan- 

 tity of carbonate of lime. 



The surface water differs chemically from the deep water 

 only in having no sulphate or carbonate of lime in its consti- 

 tution : 



Specific gravity of the deep water, . . =1.30 

 Do. of the surface, . . . = 1.23^ 



A trace of iodine and bromine was found in both. 



