WALKING ALONG THE CEILING. 



259 



A more scientific method of walking upon the 

 ceiling is suggested by those beautiful pneumatic 

 contrivances by which insects, fishes, and even 

 some lizards are enabled to support the weight 

 of their bodies against the force of gravity. The 

 house-fly is well known to have the power of 

 walking in an inverted position upon the ceilings 

 of rooms, as well as upon the smoothest surfaces. 

 In this case the fly does not rest upon its legs, 

 and must therefore adhere to the ceiling, either 

 by some glutinous matter upon its feet, or by the 

 aid of some apparatus given it for that purpose. 

 In examining the foot of the fly with a powerful 



Fig. 60. 



microscope, it is found to consist of two con- 

 cavities, as shown in Figs. 60 and 61, the first of 

 which is copied from a drawing by G. Adams, 

 published in 1746, and the second by J. C. 

 s 2 



