I02 The Great World's Farm 



table mold 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 mold may have more 

 to give, but also keeps back more. If the two contained 

 an equal amount of water, therefore, plants would actu- 

 ally be better off for moisture in the sand than in the 

 mold; but this is not the case. 



An experiment made for the purpose of trying differ- 

 ent 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 mix- 

 ture of vegetable mold and sand; and 3, coarse sand 

 alone; the loam held two and a half times as much moist- 

 ure as the sand, and the sand and mold 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 transpiration. 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, and the vegetable mold and 

 sand a fraction over twelve and a quarter per cent. 



The supply contained in the sand was exhausted first, 

 of course, because it contained so much less to start with; 

 but though the other soils were not nearly as dry, the 

 plants flagged because they could not get hold of the water 

 which they still contained. 



Some plants, such as rice, grow equally well in soil or 

 water, but most plants are injured by having their roots 



