GENERAL RULES FOR PLOUGHING. 447 



Earths. Ears. Grains. 



.Greenstone, (secondary trap,) 10 . 245 



Limestone, 9 . 251 



Chalk, 13 . 355 



Gypsum, (very sickly plants,) 6 . 40 



Sandstone, (silicious,) 12 . 230 



Pit-sand, (brown,) 12 . 210 



Blue clay, (taken ten feet under the surface,) . 10 . 242 



Mixture of all the above kinds, 9 . 190 



Common light loamy soil, 18 . 453 



&quot; Experiments of this nature seem worthy of further prosecu 

 tion, particularly relative to the respective influence of the atmos 

 phere and soil in the nourishment of plants. When the oats 

 were sown, scientific as well as practical men predicted, that in 

 most of these earths they would not grow ; and when they saw 

 them growing, predicted that they would not ripen seed. The 

 results have proved otherwise.&quot; 



A single experiment, in such case, can hardly be considered 

 as decisive, excepting as to the possibility of plants living and 

 maturing in an unmixed soil. The fact of their not succeeding, 

 with one exception, so well in a soil composed of the several 

 varieties as in a simple soil, is likewise noticeable. The superior 

 success of the plants in loam is also to be observed, to show that 

 their growth was not wholly dependent upon the atmosphere, as 

 some would have us believe, and that the soil furnishes some 

 thing more than a mere support for the plants. The growth, in 

 each case, must be considered as inferior : and, without deducing 

 any general conclusions, which might be premature, or endeav 

 oring to fit the facts to any received theory, I submit it to the 

 further inquiries of those who have the curiosity and talent to 

 pursue these interesting investigations. If it prompts to other 

 well-conducted experiments, my object will be answered. 



The bringing of any considerable quantity of inert soil to the 

 surface is obviously attended with uncertain results, so much 

 depends upon the nature and condition of the soil so brought up. 

 At the Duke of Portland s, at Welbeck, places were pointed out 

 to me where the surface mould had been removed, a portion of 

 the subsoil taken away, and the mould, or top soil, returned to 



