100 FOREST CULTURE AND 
their stomata, and stands in immediate correlation to 
the power of absorption of moisture. Besides, if the 
evaporation of Eucalyptus-trees is so enormous during 
heat, and if the often horizontal. roots of these trees 
thus render soil around them very dry, in consequence 
of the copious conveyance of moisture to the air, 
they simultaneously, by the rapidity of their evapo- 
ration in converting aqueous to gaseous liquid, or 
water into vapor, cause alowering of the temperature 
most important in our climate during the months of 
extreme heat, while their capability of absorbing 
moisture during rain or from humid air must be com- 
mensurately great. 
It is beyond the scope of this address to dwell fur- 
ther on facts like these ; but I was anxious to demon- 
strate by a mere example how much we have yet to 
learn by patient research before we will have recog- 
nized in all its details the important part which forest 
vegetation plays in the great economy of nature. 
Concerning forest culture, I would very briefly allude 
to an instance showing how, by the teachings of natu- 
ral science and thoughtful circumspection, the rewards 
of industrial pursuits may become surprisingly aug- 
mented. In the uplands of the Madras Presidency, 
an ingenious method has been adopted in gathering 
the harvest of Cinchona-bark, in recent very extensive 
plantations, by removing it in strips without destroy- 
ing the cambium layer. Then, by applying moss to 
the denuded part of the stem, not only is the remov- 
ed portion of the bark renewed within a year, to the 
thickness of three years’ growth, but the protection 
of the tender bark against the influence of light and 
air allows nearly all the quinine and other alkaloids 
