FOREST TRENS. 415 



oak — with its large leaves, that turn scarlet in the autumn — play- 

 any part in the adornment of my landscape. 



I have given an illustration of the effect of lightning discharge, 

 which occurred in the spring of 187 1, upon a Turkey oak growing in 

 the grounds of Peterborough House, Fulham (fig. 940). The electric 

 current passed down the tree and darted through the air to the iron 

 hurdles, at the base of which it made a hole in the ground. It appeared 

 to have passed through the newly forming wood, or cambium, and in 

 the act of passing from the tree to the earth separated the bark from 

 the tree. The bark is loosened all round, and a piece may be seen 

 lying at the base. I am curious to see how such an extensive injury 

 will affect the vitality of the tree, and I shall watch its career with 

 interest' I have seen the effects of many such electrical discharges on 

 trees, and this may be taken as a fair example of the damage which results. 

 It also teaches us to beware of standing under a tree in a thunderstorm. 



A Willow-tree is always associated with rivers and wet places, 

 though persons who cultivate them say the best basket willows will not 

 flourish in very wet soil. There are numerous species, — from the small 

 procumbent one which lives on the tops of the mountains of Scotland, 

 and which we grow in the alpinery, to the great Salix alba which lives 

 on the banks of our rivers. Virgil has remarked the effect of situa- 

 tion on various kinds of trees, which well indicates that the truth of an 

 observation of nature, once correctly made, will last from generation to 



generation : — 



"Nee vero terrae ferre omnes omnia possunt. 

 Fluminibus salices, crassisque paludibus alni 

 Nascuntur, steriles saxosis montibus orni ; 

 Litora myrtetis lastissima ; denique apertos 

 Bacchus amat colles, Aquilonem et frigora taxi." 



Virgil, Georgics. 



We have several species. The White Willow {Salix alba, fig. 941) 

 is the most important, as it forms a forest tree, and is rapid in 

 its growth. In midsummer, when the sun shines, every zephyr turns 

 the leaves, when the silvery whiteness of their under surface contrasts 



' Sept. 1872 : this tree is now dead. 



