Experiments 



the thickness of its earthen dome, it finds It- 

 self in broad daylight; and to it daylight 

 means the final deliverance, means liberty. It 

 strikes against an invisible obstacle, the glass; 

 and to it glass Is nothing at all and yet an 

 obstruction. On the far side, it sees free 

 space, bathed in sunshine. It wears itself out 

 in efforts to fly there, unable to understand 

 the futile nature of its attempts against that 

 strange barrier which it cannot see. It per- 

 ishes, at last, of exhaustion, without, in its 

 obstinacy, giving a glance at the gauze closing 

 the conical chimney. I must devise a means 

 of renewing the experiment under better con- 

 ditions. 



The obstacle which I select is ordinary 

 brown paper, stout enough to keep the insect 

 in the dark and thin enough not to offer seri- 

 ous resistance to the prisoner's efforts. Aa 

 there Is a great difference, in so far as the ac- 

 tual nature of the barrier is concerned, be- 

 tween a paper partition and a clay ceiling, let 

 us begin by enquiring If the Mason-bee of the 

 Walls knows how or rather is able to make 

 her way through one of these partitions. The 

 mandibles are pickaxes suitable for breaking 

 through hard mortar: are they also scissors 

 33 



