14:26 THE STORY OF THE UNIVERSE 



makes about 600 strokes with its wings every second, 

 and that it is carried through the air a distance of 

 five feet during that brief period. But, if alarmed, 

 the velocity can be increased six or sevenfold, as 

 every one must have observed, so as to carry the in- 

 sect thirty or five-and-thirty feet in the second. In 

 the same space of time, observes Mr. Kirby, a race- 

 horse could clear only ninety feet, which is at the 

 rate of more than a mile a minute. Our little fly, 

 in her swiftest flight, will in the same space of time 

 go more than the third of a mile. Now compare the 

 infinite difference of the size of the two animals (ten 

 millions of the fly would hardly counterpoise one 

 racer), and how wonderful will the velocity of this 

 minute creature appear! Did the fly equal the race- 

 horse in size, and retain its present powers in the 

 ratio of its magnitude, it would traverse the globe 

 with the rapidity of lightning. 



Bees, again, are accomplished masters of aerial 

 motion. The humble-bees, notwithstanding their 

 heavy bodies, are the most powerful fliers of this 

 class. The same excellent entomologist tells us that 

 they "traverse the air in segments of a circle, the 

 arc of which is alternately to right and left. The 

 rapidity of their flight is so great that, could it be 

 calculated, it would be found, the size of the creature 

 considered, far to exceed that of any bird, as has 

 been proved by the observations of a traveler in a 

 railway carriage proceeding at the rate of twenty 

 miles an hour, which was accompanied, though the 

 wind was against them, for a considerable distance 

 by a humble-bee (Bombus subinterruptus), not 



