THE WATER BOATMAN. 247 



the fulcrum, instead of being a rowlock affixed to the 

 side of the boat, is formed by the horny shell of the 

 insect's side. The short lever is represented by that 

 part of the limb which passes through the shell into 

 the interior of the thorax, and the stout muscles of 

 the thorax, which are fixed to the leg, take not only 

 the office, but the exact position of the arms of a human 

 boatman. 



Next, we come to a small but important point. 

 All of my readers who have been trained to the use or 

 a boat, and to 



" Feather their oars with skill and dexterity," 



must remember how much trouble they had to take in 

 order to turn the oar at the end of the stroke, so as to 

 present the edge, and not the flat side of the blade, to 

 the air, as the oar is drawn back for another stroke. 

 It is one of these things which looks absurdly easy, 

 but in which the very ease betrays the consummate 

 skill of him who handles the implement. 



In the rowing legs of the Water Boatman we find a 

 provision for feathering exactly like that of the human 

 boatman, except that the rowing limb, as made by 

 nature, is infinitely superior to the oar which is formed 

 by art. Supposing that a boat-builder could invent 

 an oar in which the blade should be very much longer, 

 wider, twice as strong, and not half as heavy as the 

 blade of a wooden oar, and that as soon as the stroke 

 was made the blade vanished altogether, leaving 

 nothing but a thin, tapering spike of wood, a tre- 

 mendous advantage would be given to the boat's crew 

 which first made use of the improved implement, 



