LIME. 



LIME. 



bushels of the limestone ; and from my own 

 experiments, I am inclined to agree in opinion 

 with many of the farmers of the midland coun- 

 ties, that the lime procured from limestone is 

 rather more powerful in its effects on clay soils 

 than that made from chalk. 



In either case the shape of the kiln, and the 

 steady gradual application of the heat, are very 

 material circumstances to be regarded by those 

 who burn their own lime. The limestone and 

 chalk should be placed in the kiln (which I 

 think is best of an egg shape), in moderately- 

 sized pieces, free from the powdered chalk or 

 stone; and care must be taken to have the 

 earth thoroughly burnt, of which perhaps the 

 best indications are its lightness, and the alte- 

 ration of the colour of the flame issuing from 

 the top of the kiln, which, when the lime is 

 sufficiently made, loses its red tinge. The 

 price of the fuel, and readiness of access to the 

 limestone or chalk, of necessity governs the 

 price of the lime: in some districts of the 

 north it is made by the farmers for not more 

 than one penny to three halfpence per bushel. 



The chemical uses of lime to vegetation may 

 be conveniently divided into two heads ; first, 

 its direct action upon vegetation ; and second- 

 ly, its chemical operation on the matters con- 

 tained in all cultivateable soils. 



In its direct action, as a food or constituent 

 of plants, its uses are highly important ; for 

 hardly a single plant lias yet been analyzed, in 

 which the presence of lime has not been de- 

 tected, in combination with an acid. It must 

 be regarded indeed as an essential ingredient 

 in almost all vegetable substances, as a direct 

 food of plants. 



It is found in the commonly cultivated crops 

 of the farmer, however, in very varying pro- 

 portions : thus the ashes of the oat-plant contain 

 more than five per cent, of lime ; in two 

 pounds' weight of the seeds of wheat are com- 

 monly found about 12 grains of carbonate of 

 lime ; in the same quantity of rye, about 13-4 

 grains ; in barley 24-8 grains ; 33-75 grains in 

 the oat, and 46-2 in the same weight of rye- 

 straw. It abounds also with magnesia in the 

 wood of trees: the ashes of that of the oak 

 contain about 32 per cent, of the earthy carbo- 

 nates; those from the poplar 27 per cent.; from 

 the hazel 8 ; of the mulberry 56 ; and from the 

 hornbeam 26 per cent. The proportion how- 

 ever of lime found in plants varies with the 

 composition of the soil on which they are pro- 

 duced. Thus the ashes of the leaves of the fir 

 (FMMM abies), growing upon a limestone hill, 

 were found to contain 43-5 per cent, of the car- 

 bonates of lime and magnesia, but the ashes 

 from the leaves of another fir growing upon a 

 granite soil yielded only 29 per cent, of the 

 same earthy salts. There are very few soils 

 fit for cultivation from which this earth is en- 

 tirely absent, and its addition is commonly 

 found by the former to promote the fertility of 

 most barren lands the most sterile heaths, for 

 these are the very lands whose soils contain 

 hardly a trace of lime ; in that of Bagshot, for 

 instance, it exists in a very minute proportion. 

 The attraction of lime for the aqueous parti- 

 cles of the atmosphere is considerable. In my 

 own experiments 1000 parts of lime previous- 



ly dried in a temperature of 212 gained bv ex- 

 posure for three hours to air saturated 'with 

 moisture, at a temperature of 60, 1.1 parts. 

 Professor Schubler found that the same weight 

 gained in 12 hours 26 parts, in 24 hours 31 

 parts, in 48 hours 35 parts, when it appeared 

 to have become saturated with moisture, for in 

 72 hours it had not again increased in weight. 

 Lime therefore is not without its uses even in 

 this respect to vegetation. Lime and chalk 

 differ in their action, and in their value as fer- 

 tilizers in several respects ; thus lime dissolves 

 and renders soluble the organic matters of the 

 soil, which chalk does not; its action, too, as a 

 direct food of plants, is more rapid, from the 

 superior readiness with which it mingles with 

 the soil. And again, its carriage is consider- 

 ably lighter, for in the process of lime-burn- 

 ing almost all the water and carbonic acid gas 

 of the chalk are driven off. These amounted 

 in some specimens of Kentish chalk, which I 

 examined, to more than 58 per cent.; so that 

 when the farmer carries 42 tons of recently 

 well-burnt lime, he conveys as much real earth 

 on to his land as is sometimes contained in 

 100 tons of chalk. 



The chemical action of the lime on the soil 

 is also very considerable; mixing with the 

 heavy adhesive clays, it renders them more 

 friable, less liable to be injuriously acted upon 

 by the sun, and much more readily permeable 

 by the gases and vapour of the atmosphere. It 

 renders them, the cultivator tells you, "more 

 easily workable." And, again, the action of 

 lime upon the organic substances always more 

 or less contained in the farmers' soils is very 

 considerable; anl this benefit is not merely 

 confined to the vegetable remains in the land, 

 but it extends with equal energy to the dead and 

 the living animal matters, with which, in a 

 countless variety of forms, the soil is tenanted. 

 There are few substances, in fact, more de- 

 structive to grub-worms, animalculae, &c., than 

 lime ; and where these are destroyed by the 

 action of the lime, the soil is, as a natural 

 consequence, enriched by their remains. On 

 soils which abound in sulphate of iron, which 

 is commonly the case with those containing an 

 excess of peat, the action of lime is not only 

 highly beneficial in decomposing or rendering 

 soluble the mass of inert vegetable remains, 

 but the lime decomposes the sulphate of iron, 

 and, uniting with its sulphuric acid, forms the 

 well-known fertilizer, the sulphate of lime or 

 gypsum of commerce. 



When quick-lime is applied to the soil, it 

 gradually becomes converted, by exposure to 

 the atmosphere, into carbonate of lime (chalk) ; 

 its action as a solvent ceases, and its presence 

 is now only useful as a direct food or consti- 

 tuent of the farmer's crops. This, however, 

 affords an opportunity for the beneficial repe- 

 tition of the dressing with lime, so far as its 

 solvent powers are available. But then, as 

 might, for the above reasons, have been antici 

 paled, the farmer finds that the after-liminga 

 never do so much good as the first; and as by 

 each successive application the lime reduces 

 still more and more the quantity of organic 

 matters in the soil, so it follows as a natural 

 consequence that after each succeeding dvess- 



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