INTRODUCTION. 133 



mensely great, extending far beyond what even the 

 imagination can conceive. It is from this cause that 

 springs, streams, and rivers that have flowed uninter- 

 ruptedly for generations through the shady forests of 

 foreign lands, and specially in Syria, Palestine, Egypt, 

 &c., were all dried up when the forests were cut or 

 destroyed by fire, and the inhabitants forced to change 

 their abodes for want of water, even for domestic 

 purposes. 



On the Marquis of Lothian's estate in Roxburgh- 

 shire, an extensive Scots pine plantation or forest was 

 formed, and as it grew up and shaded the ground, a 

 naturally damp part in the plantation gradually became 

 a spring of considerable strength, so much so that a 

 gamekeeper's house was built near by for the sake of 

 the water, By-and-by thinning was carried on, and 

 afterwards the wood by degrees was cut for estate pur- 

 poses, till the fine old plantation was nearly all cut 

 down, during which time the spring was as gradually 

 falling off as during the plantation's growth it was 

 increasing and gathering strength and volume. On 

 the same estate, and distant from the above some two 

 miles, was another well, which also increased in strength 

 as the plantation thickened around it, and again de- 

 creased as it was thinned and cut down. It is gener- 

 ally though not universally known, that the roots of 

 the trees spread underneath the ground much in the 

 same way as the branches do above it ; and it re- 

 quires no stretch of imagination to conceive how the 

 roots tfrus formed and developed under the cool shade 

 have acquired such a constitution and habit, that if 

 changed or altered in any important way (as is done 

 by the operation of thinning), effects the most baneful 

 must necessarily follow. When a single tree in the 



