182 SCIENTIFIC ILLUSTRATIONS [Inv 



The Callousness of Thievish Invaders. 



The death's-head moth (Acherontia atropos) is a thievish in- 

 vader. It makes its way into bee-hives in order to steal the 

 honey, of which it is excessively fond. Like other thievish 

 invaders, it is utterly callous. It is to no purpose that the bees 

 dart their stings at the intruder ; they only blunt them against 

 its thick skin, and soon, terrified at its presence, disperse on 

 all sides. We are too apt to applaud military invaders when 

 they are successful in enriching themselves. We award them, 

 glory for their brave incursions into other people's territory. 

 Possibly in many cases it will be discovered that the defensive 

 army was, like the bees, unequal to a vigorous resistance ; and 

 that what was called the bravery of the invaders was nothing 

 more than the exhibition of that natural callousness with which, 

 like the death's-head moth, many thievish invaders are endowed. 

 Nature has made creatures which do not feel even a just sting. 

 The death's-head moth is impervious to the righteous punish- 

 ment of the bee. Thievish invaders are inaccessible to the 

 stings of conscience. i. 



Nothing 1 Invariable. 



There is no body or part of a body whose existence can be 

 termed invariable. Wherever in the material world anything 

 seems to be unchanged, whether it is in reference to its situation 

 or its internal condition, this inaction is only apparent, as the 

 hour-hands of a clock appear to be stationary when we take a 

 cursory glance at them. This is, however, but a feeble simile 

 when we speak of changes which are hardly perceptible in the 

 course of many thousand years. so. 



The Invisible may yet be Legible. 



When, a generation since, the remnant of English troops left 

 after the then disasters at Cabul were shut up in a fort, sur- 

 rounded and vigilantly watched by their enemies, they managed 

 nevertheless to send brief letters to their nearest friends. These 

 letters to appearance were only blank pieces of paper. But they 

 uere covered with words traced with rice-water instead of ink, 



