VOYAGE TO ALGEKIA. 169 



it was of almost inky blackness black qualified by a 

 trace of indigo. 



What change does the home examination here 

 reveal? In passing to indigo, the water becomes sud- 

 denly augmented in purity, the suspended matter be- 

 coming suddenly less. Off Tarifa, the deep indigo 

 disappears, and the sea is undecided in colour. Ac- 

 companying this change, we have a rise in the quantity 

 of suspended matter. Beyond Tarifa, we change to 

 cobalt-blue, the suspended matter falling at the same 

 time in quantity. This water is distinctly purer than 

 the green. We approach Cadiz, and at twelve miles 

 from the city get into yellow-green water; this the 

 London examination shows to be thick with suspended 

 matter. The same is true of Cadiz harbour, and also 

 of a point fourteen miles from Cadiz in the homeward 

 direction. Here there is a sudden change from yellow- 

 green to a bright emerald-green, and accompanying 

 the change a sudden fall in the quantity of suspended 

 matter. Between Cape St. Mary and Cape St. Vin- 

 cent the water changes to the deepest indigo, a fur- 

 ther diminution of the suspended matter being the 

 concomitant phenomenon. 



We now reach the remarkable group of rocks called 

 the Burlings, and find the water between the shore and 

 the rocks a strong green; the home examination shows 

 it to be thick with fine matter. Fifteen or twenty 

 miles beyond the Burlings we come again into indigo 

 water, from which the suspended matter has in great 

 part disappeared. Off Cape Finisterre, about the place 

 where the ' Captain ' went down, the water becomes 

 green, and the home examination pronounces it to be 

 thicker. Then we enter the Bay of Biscay, where the 

 indigo resumes its power, and where the home exam- 

 ination shows the greatly augmented purity of the 



