236 EVAPORATION OF EVERGREEN AND DECIDUOUS TREES. 



Table III. 



"Water Evaporated in Twelve Months by various Plants — 

 Grains. 



Spruce Fir 

 Portugal Laurel . 

 Evergreen Berberis 

 Yew .... 

 Holly .... 

 Common Laurel . 

 Ilex .... 

 Larch .... 

 Oak .... 

 Deciduous Berberis 

 Ash .... 

 Sycamore . 



Water 



supplied to 



Soil. 



91-400 



156-400 



123-900 



171-400 



61-400 



181-400 



13-400 



87-400 



57-400 



137-400 



102-400 



97-400 



Water 



obtained from 



Soil. 



33-030 

 40-502 

 33-460 

 35-860 

 16-210 

 39-480 

 2-100 

 26-900 

 23-190 

 42-610 

 12-890 

 36'010 



Total 

 Evaporated. 



124-430 

 196-902 

 157-360 

 207-260 



77-610 

 220-880 



15-540 

 114-300 



80-590 

 180-010 

 115-290 

 133-410 



Table IV. 



Table showing the Period of the Year in which Evergreen and 

 Deciduous Plants Evaporate 100 Parts of Water. 



Four Mouths to April 24 



, , August 22 . 



, , December 31 



Evergreen. Deciduous. 

 23 8 



52A 56 



24i 3G 



100 100 



J. B. Lawes. 



N^ote upon the j)receding Experiments. 



The evaporating power of tlie leaves is one of the most import- 

 ant properties of plants, for on the healthy performance of this 

 function depends not merely the vigour and development of the 

 plant, but also indeed its very existence. Every new fact, there- 

 fore, which in any way tends to elucidate the chemical or phy- 

 siological nature of the leaves, or which throws light upon the 

 mode in which they act, and the effects produced by the various 

 agents to the influence of which they are naturally subject, is 

 highly interesting. The preceding experiments were undertaken 

 with a view to ascertain the ratio which exists between the eva- 



