EUCALYPTUS TREES. 101 
to remain retained in the cortical layer without de- 
composition, while in the ordinary three years’ bark 
half or more of these principles is lost. 
Facts like these lead us to appreciate the important 
bearings of the natural sciences on all branches of in- 
dustry ; but they warn us, also, to pause before we 
give our further consent to the unlimited and reckless 
demolition of our most accessible forest lands, on the 
maintenance of which so many of our industries de- 
pend. 
Just as it required, even under undisturbed favor- 
able influences, centuries before our forest riches were 
developed to their pristine grandeur, so it will need, 
in the ordinary laws of nature, at least an equal 
lengthened period before we can see towering up again 
the sylvan colosses, which eminently contributed to 
the fame of the natural history of this land—if, indeed, 
the altered physical condition of the country will ren- 
der the restoration of the treeson a grand scale possi- 
ble at all. 
Has science drawn in vain its isothermal girdles 
around the globe, or has the searching eye of the 
philosopher in vain penetrated geologic structure, or 
in vain the exploring phytographer circumscribed the 
forms ? Well do we know what and where to choose; 
botanie science steps in to define the objects of our 
choice, which other branches of learning teach us to 
locate and rear. 
The Tea would as thriftly luxuriate in our wooded 
valleys as in its native haunts at Assam, and yield a 
harvest far more prolific than away from the ranges. 
Indeed, we may well foresee that many forest slopes 
will be deéted in endless rows with the bushes of the 
