126 Roots 



Of all kinds of soils, it is those containing most 

 vegetable matter which take up most moisture, and 

 also remain damp the longest. 



It is a curious fact, however, that the soils which are 

 least ready to part with their moisture to the air are 

 also those which are least ready to part with it to the 

 roots of plants. There may be actually more moisture 

 in vegetable mould than in sand ; but the latter, at all 

 events, makes the plants welcome to what there is, and 

 lets them have almost every drop ; while the mould 

 may have more to give, but also keeps back more. If 

 the two contained an equal amount of water, there- 

 fore, plants would actually be better off for moisture 

 in the sand than in the mould ; but this is not the 

 case. 



An experiment made for the purpose of trying 

 different soils with regard to their readiness to give 

 up their moisture to the roots of plants gave some 

 very interesting results : the soils chosen were three 

 — i, loam ; 2, a mixture of vegetable mould and 

 sand ; and 3, coarse sand alone ; the loam held two 

 and a half times as much moisture as the sand, and 

 the sand and mould mixed held more than twice as 

 much. 



In these three soils were placed some tobacco plants, 

 which are very thirsty and very watery — four-fifths 

 water, indeed. Their broad, tender leaves begin to 

 droop as soon as gathered owing to their rapid tran- 

 spiration. The sand gave up the whole of the water 

 it contained with the exception of one and a half per 

 cent., and it was not until it had reached this dry state 

 that the tobacco planted in it flagged ; the other plants 

 flagged when the loam still contained eight per cent., 



