190 Correspondence — Rear- Admiral Sir William Wharton. 



"Speculation on the Origin of Ocean Basins," or he wouM have 

 given his reasons for saying so. The matter appears to me to turn 

 upon the question, whether there was a hardened crust upon the 

 earth at the time of the genesis of the moon, or whether there was 

 not. If there was, I do not see any impossibility in my explanation 

 of the origin of the oceans ; and it agrees with several remarkable 

 facts, such as the greater density of the crust beneath the oceans, 

 and this very point of the apparent rent between the Eastern and 

 Western Hemispheres. It is obvious that, if my speculation is 

 correct, we need go no further to account for the origination of these 

 great declivities. 



I would respectfully ask geologists interested in this subject to 

 refer to my article in Nature, vol. xxv (1882), p. 1543, or to chap, xxv 

 of my " Physics of the Earth's Crust," second edition, that they may 

 see what my speculation really is before rejecting it. 



0. Fisher. 



Hablton, Cambridge. 

 March 7, 1899. 



THE EASTERN SLOPE OF THE NORTH ATLANTIC BASIN: IS IT 

 A STEEP OR A GRADUAL INCLINE? 



[The Editor has received the following note from Eear-Admiral 

 Sir William Wharton, K.C.B., F.R.S., the Hydrographer of the 

 Admiralty'; and as it bears directly upon the nature of the so-called 

 'escarpment' of Professor Hull, referred to by Mr. A. J. Jukes- 

 Browne in his recent letters, and also to Mr. Hudleston's important 

 article, we think it will be perused with great interest by the 

 readers of the Geological Magazine. — Edit] 



Sir, — In reply to your question as to what is known of the 

 steepness of the slope of the eastern margin of the North Atlantic 

 Basin, and whether there are on it any submarine vertical precipices 

 7,000 feet or so in height, I can only say, in regard to the latter, that 

 while no man could affirm positively that none may exist, it is 

 certain that there is not a shred of evidence in their favour. 



In 1862, in the early days of telegraphy, H.M.S, "Porcupine," 

 commanded by Captain Hoskyn, was sent especially to investigate 

 this edge of the deep water west of Ireland, with a view to 

 ascertaining whether the slope was such as would prevent the 

 maintenance of a submarine cable laid on it. He searched the edge 

 for a distance of 180 miles, and perhaps the following sentences from 

 his report may be taken to sum up his results so far as your inquiry 

 is concerned : — 



" Much pains were taken, by sounding at short intervals, to dis- 

 cover if anything like a precipice existed. Our steepest incline 

 shows a difference of level of 3,060 feet in 2-7 miles, or about 

 19 feet in 100 feet. On the parallel of 51° 20' we have a dip of 

 7,680 feet in a distance of 14 miles. The intermediate soundings 

 give no evidence of a precipice, but a mountain of this height on 

 the land would present an imposing appearance, with perhaps some 

 steep escarpments." 



