1-2 



JOURNAL OF THE ROYAL HORTICULTURAL SOUiLTi . 



Indeed, if we now examine ibe geological niaj) of tliis area we begin 

 to see tliat the fruit lies almost wboUy on certain formations. In 

 North Kent it is on the Thanet sands and the deep loams above the 

 Chalk ; in East Kent, between Cbatham and Oanterbuiy and Sandwich, 

 it is again the Thanet sands and Chalk loams that carry fruit, with the 

 addition of a new formation — the Brick Earth. In Mid-Kent the fruit 

 lies almost wholly upon what is known as the Lovvei* Greensand. In 

 this case, howeyer, we see that it is not only the geological formation 

 that determines the presence of fruit, because if w^e follow this same 

 Greensand formation east of Sevenoaks the fruit disappears, and in its 

 place we come to barren w^astes covered with heather and pine. Any- 

 body passing through one of these fruit areas to anotlier would per- 

 ceive that the soils possess certain features in common ; they are 

 mostly what a farmer w^ould call light loams. This at once calls our 

 attention to what we may call the farmer's way of classifying soils; he 

 calls them loams, or sands, or clays, and defines them as heavy or 

 light to work. We can now give precision to this farmer's point of 

 view^ by making what w^e call a mechanical analysis of the soil, and 

 this mechanical analysis at once gives us a clue to the distribution of 

 any special crop like fruit. 



Every soil is built up of a mass of particles of various sizes, and 

 a mechanical analysis is merely a process by w^hich the soil is sorted 

 out into groups or particles of a specified size. If we dismiss from our 

 consideration for a time its chemical nature, we see that a soil consists 

 of a mineral framework of little pieces of rock of all sizes ; when these 

 are coarse and palpable w^e describe the soil as a sand; when they 

 become so fine as to be undiscernible separately by the eye and almost 

 imperceptible w^hen the material is rubbed between the fingers we get 

 a clay. A mechanical analysis sorts out all the various-sized particles 

 making up the soil, and collects them into specified groups, so that we 

 obtain for any particular soil the proportions in which these groups are 

 mixed. The grades of particles into which we have been accustomed 

 to divide soils are as follows: — 



(1) Material about | inch diameter is called Stones and Gravel, and is not 



reckoned in the analysis. 



(2) Particles between | inch and i inch diameter. Fine Gravel. 



(3) „ „ Coarse Sand. 



(4) „ lis n eh " Fine Sand. 



(^) » 625 J' 2^ " Sil^- 



(6) „ ^ioo » iiioo Fine Silt. 



(7) Particles less than j^^o i^^^h, Clay. 



Of course, in this connection the terms sand, silt, and clay possess 

 the special meanings defined above. Soils are mixtures of all these 

 grades of particles ; the coarsest sandy soil will contain some clay in 

 this special sense, while the heaviest clay soil will rarely contain 

 50 per cent, of it. The mechanical analysis of a soil simply takes up 

 the farmer's point of view when he speaks of sand or loam or clay, 

 and by reducing it to figures extends it and gives it precision. 



