13 



ON THE FOOD OF PLANTS. 



T*rt of the soil 

 decomposed. 



But earths 

 not their 

 *rod. 



Woollen n%$ 

 >ery beneiiciiil. 



L»meinjuri- 

 eus. 



txper»men>s 

 seemingly di: 



speaies of sakola, chenopudium maritimum, and two species 

 of yiesembryantkemum. 



These maritime plant* appear to decompose a part of the 

 soil in which they grow; the alkali produced by burning 

 them, or the sal sodae used in glass and soap, is evidently 

 derived by them from the muriatic salt. 



But when we see the lichen parellus fixing itself on the 

 siliceous rock, or the lichen immersus affecting as it does the 

 calcareous rock, in preference to the siliceous; whatever 

 may influence this choice, we cannot suspect, that either of 

 these rocks contribute by its decomposition to the nutrition 

 of these plants; nor as I apprehend, have we reason to ima- 

 gine, that either chalk, sand, or clay, is in any form the 

 aliment of the plants. 



Woollen rags have been found of great utility as a manure, 

 more especially for ivhcat. And in the experiments before 

 us we may observe, that sand with rags produced a cabbage 

 of two ounces, and four strong years of wheat. In clay with 

 rags our cabbage weighed four ounces, and we had twelve 

 strong years of wheat. But in what manner these rags pro- 

 duced effect it is difficult to say; for in January 1797 they 

 were not visibly decayed ; and in the month of September 

 in that year they still retained their texture. The quantity 

 we usually spread upon one acre is not more than four or five 

 ewt. ; and yet in the experience of every farmer it is found, 

 that in the first year they nearly double the crop of wheat; 

 and in the two succeeding years they yielded a visible in- 

 crease. At present, therefore, we can merely record it as a 

 fact, that woollen rags are highly beneficial to the land : but 

 we cannot pretend to say by what process they contribute to 

 the nutriment of plants. 



Lime in our experiments was clearly detrimental with 

 sand; the cabbage lived, but weighed less in January than 

 when planted in July: the wheat had two slender stems. 

 In clay with lime our cabbage lived till December, but never 

 grew. The wheat had one stem, which was extremely slen- 

 der, and the ear was diminutive. 



These facts appear discordant with the experience of far- 

 . mers in every quarter of the globe ; for lime is found to be 



an 



