THE LIBRARY. S3 



The tables on the preceding page are tabulated results 

 obtained, omitting remarks rna le on each, and on many 

 of the details of each, 



Temperature [probably Centigrade] of the air around 

 the trees. Averages of fifteen daily observations from 21st 

 August to 10th September: 



Lowest. Middle. Highest Point. Averages. 



Experiment Tree, . . 1830 1858 18'49 18'4t> 



Comparison . . 18'30 18'50 18'38 18'39 



Difference . . 0'08 O'll 0'07 



Temperature of the trees from 21st August to 10th 

 September, Average of fifteen daily observations : 



Lowest. Middle. Highest Point. 



Experiment Tree, . . . 1668 16'S3 17'57 



Comparison ... 17 '03 IH'88 17 '13 



Difference ... + 0'35 + 0'05 -0'44 



Thermometric difference between the air and the tree: 



Lowest. Middle. Highest Point. 



Experiment Tree, . . . -162 -172 -0'92 



Comparison . . . -1'27 -1'62 -1-25 



In a comparison of the two trees, it is seen that the 

 comparison birch is in its lower part as much hotter, as 

 in its upper part it is as much cooler than the tree which 

 was the subject of experiment. The higher temperature 

 of the lower part of the former is attributable to the greater 

 accumulation of heat in its greater volume; and on the 

 other hand, that in the upper part is smaller through the 

 greater diamater retarding the occurrence of the extremes/ 



There has been published also by Senor Alvarez another 

 paper entitled Transpiration de las Plantas Transpiration 

 of Plants a paper based on the works of M.. J. Dufour, 

 and on a memoir, Ueber das steigen des Transpiration stromes 

 bei holzplanzen, published in the Arbeiten des Botanishen 

 Instituts in Wurzbourg III. Heft I.; and another 

 entitled Formation de los Nitratos en las Plantas. 



