FLIGHT 31 



the broad tail of a dog may be seen lashing wildly 

 from side to side in the effort of steering round a turn 

 when under full speed. 



The act of rowing with a pair of oars leads us to 

 a partial understanding of that perfect and difficult 

 mode of movement — flight. The weight is brought to 

 bear on the oar at the rowlock ; the fulcrum is the 

 advancing blade, and the power is applied at the 

 handle. But, though far more clumsily, we can also 

 row by facing forwards, grasping the oar outside the 

 rowlock, and paddling. It is in that position that 

 birds exert their muscular force ; whilst in insects 

 there is a muscle pulling on the inside of the rowlock 

 for the forward stroke, as in ordinary rowing, and 

 another on the outside for the backward stroke. In 

 both cases the weight and inertia of the animal have 

 to be supported by the attachment of the wings to the 

 body ; the muscular force is applied near that inner 

 end, whilst the fulcrum, or point of support, is near the 

 tip of the wing, which lays hold of the elusive columns 

 of air, lifts the body, and, twisting like the sculling 

 oar to avoid the eddy, falls slightly, grips a new column, 

 and presses off against it. The faster the wing beats 

 the better grip of the air does it obtain ; for, as we 

 know by motor travelling, air becomes almost a solid 

 medium to cut a way through when our speed raises 

 its resistance to a great amount. ' Feathering ' the 

 wing, therefore, even more than the similar trick 

 with an oar, becomes a necessity if a bird is to get 

 its wing up and to the front for another of those 



