3o8 SCIENTIFIC ILLUSTRATIONS [Rul 



The Tendency of Things to Right Themselves. 



Nature has endowed things with a tendency to right them- 

 selves. Let us take an example from what happens in the case 

 of the atmosphere. By respiration, flame, putrefaction, air is 

 rendered unfit for the support of animal life. By the constant 

 operation of these corrupting principles the whole atmosphere, 

 if there were no restoring causes, would come at length to be 

 deprived of its necessary degree of purity. Some of these causes 

 seem to have been discovered and their efficacy ascertained by 

 experiment. And so far as the discovery has proceeded, it 

 opens to us a beautiful and a wonderful economy. Vegetation 

 proves to be one of them. A sprig of mint corked up with a 

 small portion of foul air, placed in the light, renders it again 

 capable of supporting life or flame. Here, therefore, is a con- 

 stant circulation of benefits maintained between the two great 

 provinces of organised Nature. The plant purifies what the 

 animal has poisoned ; in return, the contaminated is more than 

 ordinarily nutritious to the plant. Agitation with water proves 

 to be another of these restoratives. The foulest air shaken in 

 a bottle with water, for a sufficient length of time, recovers a 

 great degree of its purity. Here then, again, allowing for the 

 scale upon which Nature works, we see the salutary effects of 

 storms and tempests. The yeasty waves, which confound the 

 heavens and the sea, are doing the very same thing which was 

 done in the bottle. Nothing can be of greater importance to 

 the living creation than the salubrity of their atmosphere. The 

 agitations of the elements tend powerfully to restore to the 

 air that purity which so many causes are constantly impairing. 



N. T. 



No Rule without an Exception. 



It seems the rule amongst all creatures to desire above all 

 things to preserve their bodies intact and unhurt. Yet there is 

 an exception to this rule. The brittle star-fishes have a habit of 

 breaking themselves to pieces whenever they are alarmed. It 

 appears almost strange that such a creature should experience a 

 feeling of alarm, or indeed any mental emotion whatever. Yet 

 the brittle star-fishes are peculiarly timid, and have some instinc- 



