The Scottish Xaturalist. 175 



are found still standing as they grew. Beneath layers of coal 

 an under-clay is often found permeated by the roots of the coal- 

 forming plants. The underlying beds, however, are not always 

 clay, but sometimes sand, or limestone, permeated also with 

 roots. 



In all this we see how wonderfully vegetable life adapts itself 

 to circumstances, and it is enabled to do this because it does 

 not derive its principal substance from the soil. But in adduc- 

 ing this, we do not mean to disparage the value of certain soils 

 above others, nor the fact that by adding certain substances to 

 soils (they may, however, be entirely free from carbonaceous 

 materials,) plants may be made to produce twice or thrice as 

 much carbon and other matters as without the application of 

 such substances. Most decisive experiments regarding these 

 and similar facts have been made during a series of years by 

 Messrs. Lawes and Gilbert, at Rothamstead. 



Soils are sometimes deteriorated, but often improved by the 

 " subsoils" upon which they rest, so that the nature of the sub- 

 soil being ascertained, it can at once be seen whether deep 

 ploughing is advantageous or not. 



Natural mixtures of soils might be copied with good results. 

 Or to put it in another form, we might say, Imitate in one dis- 

 trict what nature has done for our advantage in another. For 

 instance, eight-ninths of a soil good for turnips may be siliceous, 

 and the rest lime or alumina ; then as far as practicable, clay 

 or lime might be added to the turnip-land, not as an experi- 

 ment, but with some assurance as to the result. Great improve- 

 ments in agriculture have resulted from the practical applica- 

 tion of Organic Chemistry to the developement of cultivation; 

 and this is nothing less than an attempt to simulate Nature 

 in her grand economy. The more the secrets of the conversion 

 of carbon, oxygen, hydrogen, and nitrogen into hosts of organised 

 substances are inquired into, the more it will be found neces- 

 sary to submit to, and to imitate the laws that regulate matter. 

 In many ways the vegetable kingdom stands between us and 

 the mineral (we use but one mineral as an article of food), but 

 although sulphur, phosphorus, chlorine, calcium, sodium, potas- 

 .sium, and some other elements are sometimes found in the 

 substance of plants, they occur in very small quantities. 



The destruction of the rocks has produced the soils upon 

 which plants through all time have flourished, and their ultimate 

 division and dissemination have strewn a vast variety of mate- 



