cruickshank's practical planter. 311 



der regular manuring and rotation. There are even 

 varieties of pine, such as the loblolly, which are known 

 to have an influence upon the soil where they grow 

 poisonous to succeeding crops. Mr Cruickshank 

 himself adverts several times to ground which had 

 produced a crop of timber, being boss (hollow) from 

 the roots remaining in the soil, and owing to this 

 hollowness being unsuited for replanting till the 

 roots were removed or consumed. We do not very 

 well comprehend this hollowness, and ascribe the un- 

 suitableness for replanting immediately, rather to 

 exhaustion, or to the formation of something inimi- 

 cal to vegetation, than to any hollowness or manner 

 of arrangement of the soil. 



As the causes which promote or retard the forma- 

 tion, or which tend to dissipate the earth's covering 

 of vegetable mould — a covering, on the richness or 

 thickness of which the fertility of ground, as well for 

 most kinds of naval timber as for other products, is 

 so much dependent, though of the greatest import- 

 ance — have never, that we are aware of, been gene- 

 rally brought into view, we shall devote some space 

 to their consideration. 



In the first place, to give a fair specimen of our 

 author, we shall transcribe several pages where he 



