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 LIX. On the Phcenomena of Vegetation. By Mrs. Ibbetson. 



To Mr. rUloch. 



Sir, — In two previous communications I have shown that the 

 quantity of nourishment distributed to plants was variously ar- 

 ranged between the two grand repositories, the earth and the 

 atmospliere, I have by the dissection of leaves, plainly I hope, 

 evinced that some plants receive hardly any nutriment from the 

 soil, while from the surface and sides of the leaves, and the im- 

 mense quantity of hairs with which the plants are loaded, they 

 evidently prove how much support they draw from the atmo- 

 sphere. But others on the contrary, having innumerable skins 

 on their leaves to shut out moisture, must therefore depend al- 

 most wholly on the root for that support which they cannot 

 procure otherwise. Now to complete the establishment of this 

 fact, as one to be depended on, it was necessary that the forma- 

 tion and appearance of the root of each different plant should 

 corroborate the evidence of the leaves, and answer to the idea 

 their cuticles suggested. I had hitherto neglected to examine 

 this; I had indeed dissected a great variety of roots, but it was 

 the interior that then occupied my attention, not the exterior 

 and accompaniments. It was with some trepidation, there- 

 fore, I collected twenty roots of different soils to examine and 

 inquire thoroughly into this fact. With what delight then do 

 I present to tlie public the complete confirmation of its truth ! 

 and as this requires no dissection, every person may prove the 

 justice of my assertion. But before I show the sort of root that 

 belongs to the plant of each different soil, I shall point out the 

 various v.'ays in which the juices are received by the root, and 

 the use of each separate part. 



The middle root is merely a reservoir, within which is accumu- 

 lated all that provision which supports the plant. Its office ap- 

 pears to be the receiving the collections brought to it by the 

 side roots, to arrange, compound, and extract the juices collected 

 for its apj)ropriation and selection. Next to this are the side 

 roots:— always keeping near the surface of the earth, they 

 cull the riclteit of its litjuids, and from the fat and vegetable 

 matter which usually covers the upper soil, they by means 

 of their radicula, which are generally projected upwards, draw 

 into these side roots that liquid matter which forms the sap, but 

 which is certainly dilated in the middle root ; for, if caught in 

 the preceding situation, it forms an almost jelly ; yet when ar- 

 rived at the centre it is perfectly liquefied. Thus these roots 

 bring the nutriment re(iuisite for the tree, and the matter which 



Vol. 4 5 . No. 205 . May 1815. X forms 



