ARBORICULTURE. 329 



The presence of salts, sulphur, coal, etc. may be known by 

 the absence or peculiarity of vegetation, as well as by color, and 

 the appearance of the water of such soils. 



The capacity of a soil for retaining water may 

 be thus ascertained. An equal portion of two 

 soils, perfectly dry, may be introduced into 

 two bell-glass, cylindrical vessels, (Plate 102) 

 plate cir. in the middle of each of which a glass tube 



is previously placed. The soil should be put into each in the 

 same manner, not compressed very hard, but so as to receive a 

 solidity approaching to that which they possessed when first 

 obtained for trial. If, after this preparation, a quantity of water 

 be poured into the glass tubes, it will subside ; and the capillary 

 attraction of the soils will conduct it up the cylinders towards the 

 tops of the vessels. That which conducts it the most rapidly, 

 provided it does not rise from the weight of the incumbent 

 column of water in the tube, may be pronounced to be the 

 better soil. 



CHAP II. 



Of the Different Modes of Rearing Forest Trees. 



It has been strongly controverted by some, whether it is better 

 to raise trees for timber and like purposes* from their seeds and 

 first rudiments, or to transplant such as we find have either raised 

 themselves from their seeds, or sprung from their mother roots, 

 or by grafting or innoculation. Now that to produce them 

 immediately from the seed we contend is the better way, the 

 following reasons may seem to evince. First, because they 

 vegetate the soonest ; secondly, because they produce the 

 straightest and most uniform shoots ; thirdly, because they will 

 neither require staking nor watering, which are two very 

 considerable articles; fourthly, because that transplanting in 

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