144 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[Apkil, 



THE PHILOSOPHY OF TERRA FIRMA. 



Having devoted the preceding chapters to a brief outline of tlie 

 chief primary Causes of Effects manifest within the primitive ocean, 

 and the phenomena of primitive eartlis of exclusive oceanic origin, I 

 will now pass on to the consideration of earths of Terra Firma, elabo- 

 rated by animals and vegetables, as produced by secondary causes, by 

 the moving force of waters, and atmospheric affections, produced and 

 still producing by a regular unbroken sequence of events, being the 

 continuance of the one great chain of life, and still ascending in the 

 scale of development. The primitive soils of the ocean, or more 

 plainly speaking, those which are the exclusive products of the ocean, 

 are silicates, and the eartlis of calx, and soda, forming sands and pebbles, 

 marls of varieties, limestones, calcarious matters, salts, sulphates, 

 muriates, carbonates, nitrates, and other characteristic fossil and mine- 

 ral bodies : these several matters being (separately, and under nume- 

 rous combinations,) the foundations of Terra Firma, and being the 

 secondary and co-operative causes of all terrestrial phenomena em- 

 bracing the living, fossil, and mineral kingdoms. 



Professor Brande, in his lectures, given in this Journal, has told 

 you that the presence of alumina is necessary for the generation 

 and maintenance of almost all vegetable species ; but he has not, 

 neither can he inform you, under what conditions aluminous earths 

 are formed. The oceanic earths of which I have previously 

 spoken, have no aluminous clay, nor traces of this earth in their 

 composition, unless they have been subjected to those influences 

 by which this earth is generated. The island, and the district 

 apportioned to the main continent, have not only no alumine, which is 

 absolutely necessary for the maintenance of species, but the soil when 

 first elevated above the waters, is wholly inimical to land vegetation, 

 abounding with bitter acrid salts, mechanically and confusedly mixed 

 with the alkaline earths. The conditions of change are atmos- 

 pheric influences, thus the virgin lands disposed within the hot rain- 

 less regions continue bare and desolate for a long unbroken succession 

 of ages, but where the rains fall or the lands are periodically or for 

 any prolonged period of time covered by the freshes, the acrid salts 

 rapidly disappear, contending acids and alkalies uniting, form neutral 

 bodies, and the soil rapidly acquires the generating power. Again, 

 there aie secondary causes of fertility, such as sea birds resorting to 

 the newly formed land, or masses of vegetable matter being conveyed 

 there by the tides, or thrown thereon during storms. The species 

 first generated on these desolate soils are uniformly species of man- 

 grove, being aquatic plants, nurtured and fed by saline waters, con- 

 taining much soda, and sinking within the waters in consequence of 

 their consolidated nature : with these we find rank coarse grasses almost 

 wholly composed of silica, and thorny shrubs of a dry brittle nature : 

 neither the one, or the other, produce the black vegetable soil common 

 to older strata, their chief constituents similating with ocean plants. 

 In the course of time, the soil undergoes a change more favourable to 

 vegetable existence, the dung of aquatic birds and vast quantities of 

 fish brought by them and continually spread upon the soil contributes 

 to increase this favourable disposition, and if rain, onlv occasionally 

 fall, new species more exclusively belonging to the earth simultane- 

 ously or in- succession make their appearance; acacias, gum trees, 

 aromatic shrubs, replacing the trees and plants and grasses of a more 

 decided character, as the former occupants die away, or diverge into 

 new species, in conformity to the change of soil and local inHuence. 

 The law of nature in spontaneous generation is climate and association : 

 the deserts being disposed within rainless regions continue bare and 

 desolate, except in those regions where the rains fall, where rivers 

 and fresh waters spread over the soil, or where these waters find their 

 way by percolating through the porous beds : on the other hand the 

 countless islands of the Pacific derive a rapid fertility from the rains 

 that periodically fall, as well as from each other by a variety of 

 secondary causes, such as the conveyance of vegetation from the 

 one island to the other, by the sea, by birds, and by man : — the gene- 

 ration and increase of vegetable earth depends therefore upon the 

 generation and increase of vegetable species. 



Soils of Terra Firma are the resolution of ascesent vegetables 

 generally combined with variable proportions of animal matter; of a 

 black colour; eagerly combining with the atmospheric volumes and 

 with water, by which combinations various known products are gene- 

 rated; they are bibulous, reducible to dust, inflammable, and com- 

 bustible, converted into clay, and from thence by transition into schist, 

 again decomposing and jjassing into earths and ochres: sometimes 

 ])assing into coal. Chemists by the tortuous means of fire produce 

 Jrom pure vegetable earth a definite compound, which they term 



humus, but the student must bear in mind that this compound is arti- 

 ficial, not existing in the natural state, and can only be obtained by 

 causing the separation of those acids, whicli are part and parcel of 

 the soil, and by oxydating the remainder by means of heat of fusion. 



While the living inhabitants of the ocean are continuously occupied 

 in generating consolidated gaseous and volatile products, the archi- 

 tects of Terra Firma, awakened into existence and local action, 

 become in time equally effective elaborators of earths of other quali- 

 ties than those previously existing; and in climates favourable to 

 vegetation the earths gradually accumulate, forming vast aggregate 

 masses in union with those oceanic products which they abstract 

 from the ocean soil, or that are united with them by the moving force 

 of waters. Of the numerous varieties of animal and vegetable 

 existences peculiar to the earth, to fresh water lakes, streams, rivers, 

 and even to the air, but very few retain their primary form on the 

 cessation of vital action ; of those few, some enter into the fossil state, 

 but tl'.e great majority are either devoured by animals and pass 

 through the digestive process, or they decompose, their atomic 

 particles and peculiar compounds being received by the earth, the 

 general parent and nursing mother of all — disseminating and combining 

 with each other, and with oceanic substances, as the accident of 

 locality and local influence may determine; the result of change being 

 earths, fossils, and minerals, and also aggregate masses, termed 

 mineral beds: the results produced by purely atmospheric influences, 

 varying from the results manifest in oceanic beds, the material of the 

 animal and vegetable structure being peculiar to the element under 

 the conditions of which it lives, and is enabled to propagate its kind. 

 We have seen the polypes existing by sufferance only, of latitude, 

 dip, and inclination, and such, in fact, is the general law of nature, 

 applicable to all living forms of the eartli ; and as the polypifus 

 flourish most, and as all oceanic creatures are most abundant beneath 

 tropical waters, so do we find animals and vegetables most abundant 

 in those lands situate within the tropics which are favoured with 

 excess of heat and moisture : many individual species having scarcely 

 any limits to their growth or the multiplication of kind. Time, under 

 all circumstances, is necessary for the full development of species, 

 as it is for the full development of the earth : generations elapse 

 ere the coral reef rears its head as an island or main portion of a 

 continent : generations elapse ere the forest tree attains its maturity 

 of growth, multiplies its species, and thereby generates those vast 

 beds of vegetable matter and clay which meet the view in local por- 

 tions of the earth. We have, it is true, no hills or mountains of bone, 

 the reliques of terrestrial species ; but we have masses of vegetable 

 matter equalling in extent many of the coral formations of the deep. 

 Beneath the Equatorial Band, in those localities which favour the 

 rapid generation, destruction, decomposition, and change of organic 

 bodies, these depositions of vegetable earth cover many thousand 

 square miles of the surface of the earth, and contribute in many places 

 to fill up the unfathomable depths of the ocean, being carried therein 

 by rivers of vast magnitude. The trees of the forest possess, it is 

 true, greater longevity than any known animal species, they stand for 

 ages ere they become impaired by time or general accident, but 

 during this prolonged period they are active agents of change, 

 absorbing carbonic acid and atmospheric air, and thus adding to 

 their consolidated structure, producing foliage, fruit, and flowers 

 periodically — nay, perpetually changing — the leaves, flowers, and 

 fruits falling to the earth, and adding to the vegetable earth pre- 

 viously formed, their volatile products dissipating and finally entering 

 into new combinations, and being the proximate Causes of new Results. 

 Again, vegetables constitute the food of ruminating and granivorus 

 animals, of locusts, and varieties of the insect tribes, of worms and 

 other creeping things of the earth, and of many of the birds of the 

 air: man draws largely upon it for his subsistence, and myriads subsist 

 upon vegetable alone; all adding, by the digestive process, to the 

 animal matter of which they are composed, and also to the earth ia 

 the form of soil, cast out at the draught; and, added to the soil, unite 

 with and become a portion of numerous consolidated bodies. Again, 

 the roots of plants continually decay, and are as continually regenerated 

 and extended ; thus under whatever form or disposition vegetable 

 matter is deposited on the earth, it adds its portion to the earth, and 

 thereby increases the general sum of inorganic matter. 



Animal and vegetable species of Terra Firma maintain their 

 existence on the same tenure as species of the ocean: vegetables 

 exist by the carbon elaborated by animals, as well as by the elements 

 of air and water; they also abstract matters from the soil in which 

 they exist ; and they propagate by seeds or separation of parts : 

 animal species are generated, are enabled to exist, and multiply their 

 species by devouring animal or vegetable species: thus it is, in and 

 throughout universal nature an interminable war is carried on, the 

 strong devouring the weak, the weak preying upon and existing bj 



