The Floor of the Sea 

 A.S. Laughton 



A sailor takes soundings from an Egyptian 

 boat journeying up tlie Niie in about 

 1422 B.C. The painting was found in the tomb 

 of Menna, a "fieid scribe," who made the 

 voyage up the Nile with his wife. 



Throughout the long history of travel over the sea, has there 

 been a sailor who has not wondered what marvels and mysteries 

 lie hidden by the dark and restless water beneath his ship? For 

 thousands of years speculations about the unknown depths grew 

 almost entirely out of fantasy, often based on fear of imagined 

 monsters lurking below. Without a background of facts it was 

 impossible for early sea explorers to picture what the bottom of the 

 ocean is really like. 



Yet, as today, there have always been places where the sea iloor 

 rises closer into view, and it is in these shallow regions around the 

 coasts that sailors of old had to plumb the depth of the bottom to 

 avoid running their ships onto sandbanks, jagged rocks, and reefs. 

 So it is not surprising that the earliest records of soundings appeared 

 almost as soon as the first pictorial records of ships themselves. In 

 Egyptian wall paintings we see sailors lowering a weighted line 

 over the side and calling out the depth at the moment the weight 

 touched bottom. This simple method of sounding has survived 

 over the centuries and is still used today. 



But what of those parts of the ocean far from land where the 

 depth of the water is no longer a navigational hazard? How deep 

 are these? The Greek philosophers, more interested in logic than 

 in facts gained by experiment, argued on purely logical grounds 

 that the depths of the oceans must be about the same as the heights 

 of the mountains on land, and it turns out that they were just about 

 right. Many explorers in the seventeenth and eighteenth centuries 

 attempted to find the depth of the bottom in the open ocean but 

 failed because their sounding lines were not long enough. Captain 

 Constantine John Phipps, later Lord Mulgrave, in command of 

 H.M.S. Racehorse on a voyage towards the North Pole, in 1775 



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