Myth of the Ship-holder. 297 



3 feet to the shark's 6. Argument is not needed to establish 

 the idea of a " brake/' The figure is from a note by It. I. 

 Geare in 'Scientific American' for 1902. Mr. Geare 

 remarks that the shark often becomes "emaciated from the 

 strain of pulling these uninvited guests around." However, 

 it should be stated that in the figure here given theEcheneis 

 is much larger in proportion to the size of the shark, so far 

 as my experience goes, than is the case ordinarily. Eeheneis 

 is known to attain a length of 3 feet. A Rcmora half that 

 size would be extraordinarily large. On the other hand, 

 however, mention should be made of the fact that, while 

 these semi-parasites are small, not infrequently several may 

 be found on one shark. On a shark taken at Tortugas I 

 found three, while one at Key West was infested with four, 

 the largest about 30 inches long. 



Scattered throughout ancient and mediaeval literature are 

 a number of more or less isolated explanations of submarine 

 cliffs, of magnetic rocks, and of supernatural and inexplicable 

 forces which held vessels as if anchored. These are widely 

 scattered and little emphasized, aud it does not seem worth 

 while to go into them. A fair example is that of Kecker- 

 lnann (1614), who alleges that the rtemora sticking to the 

 stern of the vessel pours out a very viscid and cold humour 

 which causes the water around the rudder to be congealed, 

 making the vessel to lose steerage. Again, Johnston (1657) 

 notes that the lode stone has the power of attracting things, 

 and thinks that the Re mora has some such non-understand- 

 able power. 



Fourth Explanation: "Dead-Water." 



From the foregoing accounts no one can doubt that a 

 school of Remoras attaching themselves to a small vessel 

 can seriously arrest it in its course, but that they could 

 noticeably retard a large sailing-vessel or a steamer is absurd. 

 However, there is not lacking evidence from the days of Pliny 

 to the present time that large sailing-craft and in our times 

 even steamboats have been mysteriously checked in their 

 courses and even stopped almost or quite still. These being- 

 facts, it is necessary to find an explanation for them. This 

 is to be found in the " Dead-Water" of sailors. 



The phenomenon of " Dead-Water," in which a sailing- 

 vessel loses velocity and in a light wind may even come to a 

 stop, and in which even a steamer may be retarded, has long 

 been known to seamen. Probably the earliest notice of this is 

 to be found in Chapter X. of the ' Agricola' of Tacitus, where, 



