620 



FARMERS' REGISTER 



[No. II 



Soluble matter, principally common 

 enh and vp<^etable extract - 3 



Gypsum . - _ 2 



81 



Amount of all the products 379 

 Loss - - 21 



The loss in this analysis is not more than usually 

 OL'curs, and it depends upon the impossibility of 

 collecting the whole quantities of the different 

 precipitates, and upon the presence of more mois- 

 ture than is accounted for in the water of absorp- 

 tion, and which is lost in the different processes, 



"When the experimenter is become acquainted 

 with the use of the different instruments, the pro- 

 perties of the re-agents, and the relations between 

 the external and chemical qualities of soils, he 

 will seldom find it necessary to perform, in any 

 one case, all the processes that have been de- 

 scribed. When his soil, for instance, contains no 

 notable proportion of calcareous matter, the action 

 of the muriatic acid (7) may be omitted. In ex- 

 amining peat soils, he will principally have to at- 

 tend to the operation by fire and air (8) : in the 

 analysis of chalks and loams, he will often be 

 able to omit the experiment by sulphuric acid (9); 

 and when a soil is extremely dense and heavy, 

 and after being heated to redness, stronffly attract- 

 ed by the magnet, he must particularly attend to 

 the quantity of iron it contains ; and, in this case, 

 the muriatic acid will be the principal agent. 



In the first trials that are made by persons un- 

 acquainted with chemistry, they must not expect 

 much precision of result. Many difficulties will 

 be met with ; but in overcoming them, the most 

 useful kind of practical knowledge will be obtain- 

 ed ; and nothing is so instructive in experimental 

 science as the detection of mistakes. The correct 

 analyst ought to be well grounded in general che- 

 mical information ; but, perhaps, there is no bet- 

 ter mode of gaining it, than that of attempting 

 original investigations. In pursuins his experi- 

 ments, he will be continually obliged to learn the 

 properties of the substances he is employing or 

 acting upon ; and his theoretical ideas will be 

 more valuable in being connected with practical 

 operations, and acquired for the purpose of dis- 

 covery. 



Plants, being possessed of no locomotive pow- 

 ers, can grow only in places where they are sup 

 plied with food ; and the eoil is necessary to their 

 existence, both as affording them nourishment and 

 enabling them to fix themselves in such a manner 

 as to obey those mechanical laws by which their 

 radicles are kept below the surface, and their 

 leaves exposed to the free atmosphere. As the 

 systems of roots, branches, and leaves are very 

 diflTerent in different vegetables, so they flourish 

 most in different soils ; the plants that have bulb- 

 ous roots, require a looser and a lighter soil than 

 puch as have fibrous roots ; and the plants possess- 

 ing only short fibrous radicles demand a firmer 

 soil than such as have tap roots, or extensive la- 

 teral roots. 



A good turnip soil from Holkham, Norfolk, af- 

 jorded me 8 parts out of 9 siliceous sand ; and 

 the finely divided matter consisted 



Of carbonate of lime - - 63 



— silica - - - - 15 



— alumina - - - 11 



— oxide of iron - - 3 



Of vegetable and saline matter - 5 



— moisture . . _ 3 



I found the soil taken from a field at Sheffield 

 Place, in Sussex, remarkable for producing flou- 

 rishing oaks, to consist of six parts of sand, and 

 one part of clay and finely divided matter. And 

 100 parts of the entire soil submitted lo analysis 

 produced, 

 Silica - - - - 54 



Alumina - - - 28 



Carbonate of lime - - 3 



Oxide ol' iron - _ - 5 



Decomposing vegetable matter - 4 



Moisture and loss - - - 6 



An excellent wheat soil from the neighborhood 

 of West Drayton, Middlesex, gave 3 parts in 5 of 

 siliceous sand ; and the finely divided matter con- 

 sisted of 



Carbonate of lime - - 28 



Silica - - - - 32 



Alumina - - - 29 



Animal or vegetable matter and moisture 11 

 Of these soils the last was by far the most, and 

 the first the least, coherent in texture. In all 

 cases the constituent parts of the soil which give 

 tenacity and coherence are the finely divided mat- 

 ters; and they possess the power of giving those 

 qualities the highest degree when they contain 

 much alumina. A small quantity of finely divided 

 matter is sufficient to fit a soil for the production of 

 turnips and barley ; and I have seen a tolerable 

 crop of turnips on a soil containing 11 parts out of 

 12 sand. A much greater proportion of sand, 

 however, always produces absolute sterility. The „ 



soil of Bagshot heath, which is entirely devoid of I 

 vegetable covering, contains less than one-twen- 1 



tieth of finely divided matter. 400 parts of it, which 

 had been heated red, afforded me 380 parts of 

 coarse siliceous sand, 9 parts of fine siliceous sand, 

 and 11 parts of impalpable matter, which was a 

 mixture of liirruginous clay with carbonate of lime.* 

 Vegetable or animal matters, when finely divided, 

 not only give coherence, but likewise soilness and 

 penetrability ; but neither they nor any other part 

 of the soil must be in too great proportion ; and a 

 soil is unproductive if it consist entirely of impal- 

 pable matter. 

 Pure alumina or silica, pure carbonate of lime, 



* Wtien tfie climate is favorable and there is suffi- 

 cient moisture, shrubs occasionally grow and flourish 

 in soils nearly purely siliceous. As a striking exam- 

 ple, I may mention the soil of the cinnamon garden in 

 the neighborhood of Colombo, in the island of Ceylon. 

 In many spots where this valuable plant flourishes 

 most, the surface of the ground is white as snow, be- 

 ing pure quartz-sand; below the surface a few inches, 

 wfiere the roots penetrate, the sand is of a gray color. 

 A specimen of this, dried thoroughly, was found to 

 consist of 



98-5 Siliceous sand 



1-0 Vegetable matter 



0-5 Water. 

 In my work, entitled " An Account of the Interior of 

 Ceylon," other instances are given of soils, composed 

 chiefly of siliceous earths, admitting of cultivation in 

 that climate. Reflecting on this, I arA disposed to 

 think that in estimating the power of a soil, in rela- 

 tion to fertility, great attention should be paid to si- 

 tuation, in connexion with water. Probably a nearly 

 pure siliceous soil may be fertile which admits of be- 

 ing well watered, care being taken to give it manure - 

 Vide p. 622.— J. D. 



