432 Eev. A. M. Norman on the Voyage of 



tion of the number of revolutions by the circumference at once 

 gives the depth. The advantages of the use of the wire are evi- 

 denced, 1st, in the rapidity with which the sounding is effected, 

 the lead descending at the rate of about 175 metres (say 94 

 fathoms) in a minute, whereas with the ordinary hemp line 

 it would be about 60 metres in the minute, and being wound 

 on the wheel again at the rate of about 85 metres in the minute; 

 2ndly, in that the friction of the water upon the fine wire is 

 reduced to a minimum, and that consequently nearly absolute 

 perpendicularity of the sounding is secured ; 3rdly, the hand 

 feels with much greater certainty than with a rope the moment 

 when the lead reaches the bottom ; lastly, the greatly reduced 

 size, and consequent compactness, of the whole machine, 

 which, instead of encumbering the deck, as is necessarily the 

 case when a drum is used on which there are coiled some 

 thousands of fathoms of rope, the drum on which the wire is 

 coiled has only the breadth of an ordinary cart-wheel. 



The directions given to the Commission having been to 

 examine that portion of the Gulf lying off the northern coast 

 of Spain, the soundings and dredgings were limited to a dis- 

 tance of about fifteen miles from land. In the fortnight's 

 operations more than 100 soundings were taken, at depths 

 ranging (roughly) from 150 to 2700 metres. The results of 

 these soundings will, when published, be very interesting to 

 the hydrographer and to all interested in Physical Geography. 

 As a general observation, it may be stated that, off St. Sebas- 

 tian and Santander, where the general range of the Pyrenean 

 mountains and their outliers is at an angle with the coast, 

 the sea-bottom is found to descend with great rapidity down 

 to a thousand fathoms and more, while further west, where 

 the Cantabrian mountains run parallel with the coast, the 

 increase of depth is very gradual, so that from a little to the 

 west of Santander, and thence reaching to Cape Penas, the 

 sea-bottom of the district examined was a plateau with a 

 nearly uniform depth of 60-80 fathoms. 



A remarkable ravine in the sea, about twelve miles north of 

 Bayonne, has long been known under the name of the Fosse de 

 Cap-Breton. The ravine runs at right angles to the coast, 

 cutting in two by its narrow channel a great shallow plateau, 

 and extends from the shore seawards about three miles, with 

 a depth of 100-200 fathoms. This ravine had been the scene 

 for many years past of extensive dredging operations by the 

 Marquis de Folin, who had there procured great numbers of 

 Invertebrata of the highest interest ; and it was the great suc- 

 cess which had attended the investigations of the Marquis in 

 this spot which in a great measure induced the French 



