NATURAL BI3TOBI OP COMMERCE. 



... 





NATURAL HISTORY OF COMMERCE. 



CHAPFKK 111. (dMlb 

 THB EFFECTS or o EG LOUT ON THK INDUSTRY or THB BBITISH 



PEOPLE (co,,/i,, 



Uelation of Geology to Agriculture (oonlmuwl) Influence of certain 

 Constituent* of Book* on the Growth of Plant* Inorgaaio Matter 

 iit various specie* of Plant* Comparison between other Countries 

 and part* of Great Britain General Summary of Minerals and 

 MotaJu exported mid produced in 1887. 



Influence of certain Constituents of Rocks ontlie Growth 



of rinntx. 



Rocks may be viewed under a threefold aspect sili- 

 argilhuvous, and calcareous. Siliceous rocks of 

 Mill naturo produce light soils, which are the least pro- 

 tluctivr; whilst the hard, intractable grits form little 

 soil, because they are difficult to decompose, and that 

 little is to a great extent barren. The slaty rocks pre- 

 sent the same superficial aspects as those of the hard 

 grits; but the soft argillaceous soils, from their power 

 of retaining water, are heavy, and are usually laid out 

 into permanent pasture-lands. The pure calcareous 

 strata, aS chalk, though forming soils ranking amongst 

 our richest, are not to bo compared with those resulting 

 from the disintegration of the less pure. 



(a) Inorganic Constituents of Plants. 



A plant is compounded of two sets of constituents, 

 the organic and inorganic; the former is derived from 

 water and the atmosphere, whilst the latter is obtained 

 from the soil. Now the quantity of inorganic food re- 

 quired by different vegetables is greater or less accord- 

 ing to their nature; and if a soil be of such a kind that 

 it can yield only a small quantity of this inorganic food, 

 then those plants only will grow well upon it for which 

 this small supply will prove sufficient. Thus trees may 

 grow where arable crops often fail to thrive, because 

 many of the former require and contain comparatively 

 little inorganic matter. 



TABLE OF THE PROPORTION OF INORGANIC MATTER IN 

 1,000 LBS. OF THE FOLLOWING SUBSTANCES. 



Wheat, about 

 Oats . . 

 Barley . 

 Beans . 

 Clover . 



Ibs. 



20 

 40 

 30 

 30 

 90 



IDS. 



. 2 

 to 3 



. 50 

 60 

 50 



Pea* . . 



Turnips . 

 Aah Wood 

 Elm Wood 

 Elm Leave* 



ll.s. 



.50 

 5 to 8 

 1 to 6 

 . 19 

 . 100 



Oak Wood 

 Pine Wood 

 Wheat Straw 

 Oat 



Barley 

 Meadow Hay, 50 to 100 Ibs. 



From the above table it appears that the quantity of 

 inorganic matter varies in different parts of the same 

 plants as for example, the straw of our crops contains 

 more ash than the grain. In trees and plants tho leaves 

 are richer in inorganic matter than the wood or stalk. 



The quality of the ashes of plants varies with the 

 same conditions by which its quantity is affected. The 

 more commonly occurring mineral substances in them 

 are phosphates of lime, soda, potash, and magnesia; 

 carbonates of soda and lime ; chlorides of potassium and 

 sodium ; sulphates of soda and potash; iron and silica. 



TABLE Oy THE QUANTITY OF INORGANIC MATTER IN VARIOUS 

 SPECIES OF PLANTS. 



We conclude from the foregoing that a crop of wheat 

 will extract from the toil certain ingredient*, while bean* 

 and potatoes will extract other*. Hence a piece of land 

 may uuit ono kind of crop, and not another. Hence, 

 aiso, two ucceaeire crops of different kinds mar grow 

 well where it would greatly injure the soil to take two 

 in succession of the same kind. It is also evident from 

 the above table that the cereals contain phosphates, and 

 that there is much potash in potatoes and turnips; while 

 beans, and most leguminous planU, contain lime. 



AM the straw of cereal plants contains comparatiTerr 

 little of some of the ingredient* found in the ear, such 

 OH limo, magnesia, and phosphoric acid the straw and 

 husk being especially rich in silica so the roots may 

 in certain plants and in certain soils succeed in fully 

 nourishing the straw, while they cannot fructify the ear; 

 or the very reverse of thin may occur. 



(b.) Sources of the Inorganic Coiutituents of PlanU a**l 

 tJte Agricultural Capabilities of Soil* derived from various 

 Geological Epochs. 



As the inorganic compounds are derived from the soil 

 or from manure supplied to it, the adaptation of certain 

 crops to given land will be dependent upon the chemical 

 composition of the rock from which the soil is derived. 

 Soils derived from rocks devoid of phosphates cannot 

 produce cereals, whilst soils derived from the decomposi- 

 tion of rocks that contain the inorganic constituents of 

 cereals are necessarily the best adapted for the growth 

 of such crops. 



Dr. Daubeny experimented upon the relative amount 

 of phosphoric acid obtained from barley sown in pal* 

 verised samples of various strata of different geological 

 epochs, and no found that whatever the age of the rock 

 might be, provided it belonged to a series in which 

 organic remains were present, phosphoric acid was one 

 of the constituents of the rock. On the other hand, 

 phosphoric acid was absent in certain slates which lie 

 below the oldest rocks in which organic remains have 

 been detected such, for instance, as those of Nant 

 Francon, Llanberis, near Bangor, to the north of Dol- 

 gelly; schist taken from the foot of Snowdon; mica- 

 schist from Loch Lomond ; and certain specimens from 

 the Longmynd Mountains. 



The reclamation of those great tracts of land, the peat- 

 bogs in Ireland, for the purposes of agriculture has occu- 

 pied a very large amount of attention ; but the progress 

 of chemistry in later years has divested the question of 

 much of the paramount importance that was formerly 

 attached to it ; for now that by the researches of Liebig 

 and others the true principles of the growth of agri- 

 cultural crops are understood, it is well known that, 

 even if thoroughly drained, peat will not supply the 

 materials necessary for the production of food, and that 

 the cost of introducing those materials in the form of 

 manures, if applied to land in better condition occupying 

 the same area, will yield greater and more profitable 

 returns. 



An examination of the chemical components of the 

 following rocks, the soils of which form our finest corn- 

 growing lands, will show the practical advantage of geolo- 

 gical and chemical knowledge, and explain the great differ- 

 ence in the respective producing powers of such soils : 



Carbonate of Lime 

 Magnesia 

 Sulphate of Lime 

 Alumina . 

 Phosphoric Acid 

 Soluble Silica . 

 Insoluble Silica 



later. Oolite Great Oolite. 



M 



fj 



4-14 



M 



vn 



SM 



1-40 



1M 



MM 

 771 

 Ml 



m 



1SS1 

 MPJ 



97 N.I 



