GROWTH OF THE OAT-PLANT. 



51 



the plant, should alter and increase, by fits and starts, 

 from one day to another. We are led rather to assume 

 that the oat-plant is subject in its developement to the 

 same law which we have observed in the case of the 

 turnip, and that therefore, in the second half of the first 

 stage of growth, the activity of the leaves was princi- 

 pally directed to the production of organisable matter, 

 to be stored up in the root in the shooting stage, and 

 then supplied to the overground organs of the plant. 

 The heightened assimilative or working power of the 

 plant, consequent upon the higher temperature and 

 brighter sunshine of summer, was attended by a pro- 

 portionate increase in the supply of food ; but the rela- 

 tive proportion of the soil constituents remained much 

 the same as in the turnip plant. 



If we compare the respective quantities of potash, 

 phosphoric acid, and nitrogen, which the* overground 

 parts of the oat-plant have received from the root and 

 the soil, in the several stages of growth, i. e. to the 

 commencement of flowering, thence to incipient ripen- 

 ing, and finally to maturity, we find that 1,000 plants 

 have received : 



These proportions show that the daily increase of 

 potash in the overground parts of the oat-plant was 

 pretty nearly the same in the 21 days of the 3rd and 

 4th stages, as in the 61 days of the 1st and 2nd. But 

 for the phosphoric acid and the nitrogen a very differ- 

 ent result is obtained ; we find that the quantity of 

 these two ingredients which passed into the stalk, the 

 ear, and the leaves, amounted in the 21 days of the 3rd 

 and 4th stages to as much as in the 61 days of the 1st 

 and 2nd stages : in other words, the overground organs 



