( 17.5 ) 



With regard to the fize of thefe cxcefTively minute rndicles, I 

 made the following eftimate, as far as my eye could judge. Suppohng 

 the diameter of them to be as i, that of the larger root from which 

 they proceeded muft be confidered as 20, and conl'cquently, 4,00 of 

 tliefe flender radicles taken together were equal to the fize of the larger 

 root. Now, the diameter of this larger root being, as before ob- 

 lerved, the fixticth part of an inch, 3600 of thofe roots will be equal 

 to a cylinder of an inch diameter ; and if tliis number be multiplied 

 by 400, it follows, that 1,4,40,000 of the fmallell radicles are alto- 

 gether equal to a cylinder the fize of an inch. 



This being the cal'e, we may naturally conclude, that when any 

 plant is pulled up by the roots, luch flender radicles as thefe, not 

 only efcape our fight, but mufl: almoft: all be broken off, unlefs the 

 earth or moilt land whicli lurroiaids them adhere to, or is taken up 

 With tiiem. 



Aftei- thefe very flender radicles I have defcribed, had remained in 

 the tube three or four days, thole parts of them which did not touch 

 either the fandor the glafs, and were expofed only to the air within 

 the cavity, were lb dried up and contra6led into irregular forms, 

 that they a])peared like parcels of wool, or the threads of Hne linen 

 tangled together. 



In the month of April, I took up in a field, wliich in the preceding 

 autumn had been fovvn with Wheat, fome of the young blades or 

 Ihoots, with their roots, and the earth adhering to them : and upon ex- 

 amining thefe, 1 obferved notliing vifible, except the largelt Ihoot or 

 parent plant, which was by far the largefl, and had fliot up much the 

 higheft. To Ihew the ,fize of this plant, I caufed a drawing to be 

 made of it, which is to be feen at fig. 7,,WXYZ; and in this 

 plant the blade being fliot up to the height of about four incites, 

 the joints, or knots in the fialk, were already formed, the young ear 

 lying at the end next to the root, at W. 



