Observations on Colonel Taylor'' s Letter, 65 



crop (no matter of what) the richer the land is left ; 

 the grain thrives best through tap rooted grass." I give 

 this as their idea — for Mr. Taylor's experiment, '' Sep- 

 tember 17th to 5th October" [and many might be ad- 

 ded] disprove one, at least of their principles. The 

 wheat was worst among the plaistered bird-foot clover 

 [_"- whyy^'] They say, that " vegetable cover excludes 

 heat, and admits light ; and these are distinct elemen- 

 tary substances, though generally found together. 

 Light, with hydrogen and carbon (the materials of oil J 

 is the vivyfying power of vegetation ; but radiant heat 

 is hostile. Enough light is admitted under the cover, 

 and radiant heat is excluded." Although it cannot be 

 denied that light is essential to the life and growth of 

 plants, which can be raised to maturity in caves, by 

 lamp light, it does not fertilize the soil. They do not 

 make allowance, either, for the exhaustion of a heavy- 

 crop. What will they say to Mr. Taylor's dead cover of 

 cedar Sec ; or to a door, or board, lying on the surface ; 

 and fertilizing ; by preventing evaporation, and the ex- 

 traction by the sun [or a crop] of w^hat the air impreg- 

 nates ? And yet admitting, not light but, the acidified 

 gases, carbon he, which create and support vegetable 



^ To the " wAz/" of Mr. T. I have no decisive or techni- 

 cal answer. Probably, the under crop of grass prevents from 

 perspiration, and stagnates in the lower joints of the wheats 

 stalks, more juices than can circulate through the plant* 

 There are gi'eater demands for food, by both plants^ than the 

 earth can supply. The strongest and most forward plant ob- 

 tains the mastery. Thick and strong wheat, often choaks clo- 

 ver. H, P, 



VOL. II. I 



