The Colour of the Sea 129 



;ng arrived at the surface and following the south-westerly 

 drift of the surface water, exposure to the sun raised the tem- 

 perature of the water and discharged its colour pari passu. 

 It was evident that there was here a case of the rising of deep 

 ither coast of an ocean, away from which the 

 prevailing wind was continually driving the surface water. 



From Mogador the "Dacia" proceeded to the "Seine 



Bank," in Kit. 33" 47' N., long. 14 i' W., and explored it 



thoroughly. Among the specimens brought up on the grapnel 



were masses of dead coral and shells, all having the same green 



colour. Some of these fragments were preserved in spirit, 



which quickly assumed the green colour, leaving the shells 



and coral practically decolourised. I sent the bottle, with 



the specimens and spirit, to my friend Prof. W. N. Hartley, 



in Dublin, who was good enough to subject them to spectro- 



scopic examination. He wrote to me on February 15, 1884: 



"I have made a spectroscopic examination of the colouring 



matter you sent me and have no doubt that it is altered 



chlorophyll. I have got identical wave-length measurements 



absorption band witli your liquid and a specimen of 



pure chlorophyll dissolved in ether"; and he adds, 



" there is very little real substance in even a dark green solution." 



As the year 1884 belongs now to the remote past, I recalled 



the matt, i t> I'n.f H.utltv, and, confirming his previous 



ion, he added: "I beli \ my impression at the time 



was that the chlorophyll was the colouring matter of a living 



micro-organism, and that these settled upon the shells, but 



they were floating in the sea water." 



i obliged to Prof. Hartley for kindly permitting me to use 



these private communications. Further infniin.mon will be 



found in his paper on chlorophyll from the deep sea (Proc. 



Roy. Soc. Edin., 1885, xm. 130). 



Prof. Ht port furnished a remarkable contirn 



rst impression in so far as it ^h<>\\< .1 that the green 

 water of the Mogador coast owed its colour to the same substance 

 as did the diatom-crowded water of the Antarctic, namely, 

 chlorophyll 



\pril and May of 1885 I made a coasting voyage from 

 B. in. 9 



