LECTURE II. 57 



cannot be supposed to have that sense very deh- 

 cate. In flj'ing through the middle of a narrovir 

 passage which turned at right angles, the Bats 

 regularly bent their flight at the curvature, though 

 two feet distant from the walls. They discovered 

 holes for their retreat ; found a resting-place on 

 the cornice; avoided the branches of trees sus- 

 pended in a room; flew through threads hung 

 perpendicularly from the ceiling, without touching 

 tliem, though they were scarcely at a greater 

 distance from each other than that of their ex- 

 tended wings ; and when the threads were brought 

 nearer, they contracted their wings to pass through 

 them. They equally avoided every obstacle, 

 though the whole head was covered with a varnish 

 made of Sandarach dissolved in spirit of wine. 



" The ear could not have discovered a cor- 

 nice^ or the threads; this sense therefore does not 

 compensate the want of vision. Besides, Bats 

 fly equally well when the ear is most carefully 

 ' covered. The smell might possibly assist them; 

 for when the nose was stopped, they breathed 

 with difficulty, and soon fell. While they did fly, 

 however, they avoided obstacles very v/ell; and 

 the smell could scarcely have assisted them in dis- 



