THE FIR TRIBE. 353 



mist will soon find his eyelashes and hair covered with 

 small drops of water, while the rest of his person remains 

 dry ; if he examines the ground, he will also find that the 

 blades of grass by the wayside are fringed with dew-drops, 

 while the road itself is quite free from moisture. This 

 phenomenon is owing to the excessive radiation of heat 

 from bodies which present a large surface in proportion to 

 their bulk, and the consequent condensation of moisture 

 on'cold substances. Precisely the same effect is produced 

 on the leaves of the Firs, which are therefore said, though 

 inaccurately, to attract moisture ; the true state of the 

 case being that they are reduced to a low temperature by 

 excessive radiation of heat into space, and are consequently 

 subject to a constant deposition of moisture in the shape 

 of clear globules, which soon becoming too heavy to re- 

 main suspended on the leaves, fall to the ground, and, 

 having supplied the scanty soil with a sufficiency of 

 nourishment for the thirsty roots, trickle away in little 

 rills. These either sink into the ground, and reappear 

 below as mineral springs, or flow along the surface, con- 

 tinually increasing from the accession of similar tribu- 

 taries, and fertilizing the valleys through which the very 

 same mists had previously been carried, where they had 

 encountered no substances of a temperature low enough 

 to arrest their progress. 



There is yet another peculiarity of the Fir-tribe con- 

 nected with this subject which deserves notice. The 

 perfection of the Fir, as has been already noticed, consists 

 in height rather than lateral expansion. In all other trees 

 (except the Palms) a bud is produced in the axil of every 

 leaf. This is not the case in the Firs, but buds are 

 produced very sparingly, and nearly always at the ex- 

 tremities of the shoots. Provision is thus made for the 

 upward growth of the tree, but not for its lateral ex- 

 pansion. In other trees, again, the unfolding of all the 

 buds on an individual is simultaneous, or nearly so ; but 

 in the case of the Fir-tribe, " the bud which terminates 

 A A 



