2. OFROOTS. Parti. 



roots, and creeping or Jibrous-roots. The former, which are gene- 

 rally fingle, run down almoft perpendicularly into the earth, and 

 the latter branch out horizontally, whence they are likewile called 

 horizontal-roots. 



The Roots which proceed- immediately from the feed, are always 

 of the carrot or tap kind. Tap roots ftrike down perpendicularly 

 into the earth, 'till it becomes too hard to admit of their farther 

 pailage : but when the foil is deep, and eafily pierced, they penetrate 

 ibmctimes to the depth of feveral yards, unlefs they are cut or 

 broken, in which cafe they alter their direftion. This is frequently 

 obferved ; particularly in plants raifed in water only. The tap-roots 

 Ihoot out branches which extend horizontally; and thefe branches 

 are ftronger, in proportion as they are nearer to the furface of that 

 depth of earth which is flirred by the plough or fpade. 



Thefe are the roots which we call creeping, or fibrous. They 

 extend fometimes to a confiderable diftance from the plant that pro- 

 duces them : but then they become fo minute, that the naked eye 

 can no longer trace them ; efpecially when they have taken the 

 tindlure of the earth that furrounds them, as they generally do. 



A Carrot, for example, which feems to have only one great root 

 furnifhed with fome fibres, pufhes its roots, according to Mr. Tull, 

 to a confiderable diftance : but they grow fo very flender, that they 

 cannot be diftinguiflied from the earth that covers them, without 

 great attention. The cafe is the fame with almoft all plants. To 

 be convinced of this, and at the fame time to know how far the 

 roots of any plant can extend in ground that has been well loofened 

 by the plough or fpade, one need only make the following, or fome 

 other fimilar experiment. 



Take a piece of ground that has not been broken up for a long 

 time, and dig in it a triangular fpot, 80 feet long, 12 feet wide at 

 one end, and ending in a point at the other. Sow 20 turneps in 

 the length of this fpot, and let the earth round them be frequently 

 dug and well hoed. When the turneps are come to their full 

 growth, if that which is next the point is found to be the fmalleft, 

 and the others are gradually bigger as they ftand nearer to the part 

 of the triangle, that is, for inftance, four feet wide, it may be con- 

 cluded that the roots of thofe bigger turneps have fpread two feet 

 on every fide : and if the turneps are nearly of the fame fize from 

 thence to the wideft end of the triangle, it will be reafonable to fup- 

 pofe that their roots have not extended above two feet. 



1 The 



