238 SCIENCE OF GARDENING. PART II. 



the atmospheric temperature and pressure were nearly the same as at the commencement 

 of the experiment. Some water rushed in ; and on expelling a little air by heat from the 

 tube, and analysing it, it was found to contain only seven per cent, of oxygen. The 

 water in the tube, when mixed with lime-water, produced a copious precipitate ; so that 

 carbonic acid had evidently been formed and dissolved by the water. 



1130. Manures from animal substances, in general, require no chemical preparation to 

 fat them for the soil. The great object of the farmer is to blend them with the earthy 

 constituents in a proper state of division, and to prevent their too rapid decomposition. 



1131. The entire parts of the muscles of land animals are not commonly used as manure, 

 though there are many cases in which such an application might be easily made. Horses, 

 dogs, sheep, deer, and other quadrupeds that have died accidentally, or of disease, after 

 their skins are separated, are often suffered to remain exposed to the air, or immersed in 

 water, till they are destroyed by birds or beasts of prey, or entirely decomposed ; and in 

 this case, most of their organised matter is lost for the land in which they lie, and a con- 

 siderable portion of it employed in giving off* noxious gases to the atmosphere. By 

 covering dead animals with five or six times their bulk of soil, mixed with one part of 

 lime, and suffering them to remain for a few months ; their decomposition would impreg- 

 nate the soil with soluble matters, so as to render it an excellent manure ; and by mixing 

 a little fresh quick lime with it at the time of its removal, the disagreeable effluvia would 

 be in a great measure destroyed ; and it might be applied in the same way as any other 

 manure to crops. 



1 132. Fish forms a powerful manure, in whatever state it is applied ; but it cannot be 

 ploughed in too fresh, though the quantity should be limited. A. Young records an ex- 

 periment, in which herrings spread over a field, and ploughed in for wheat, produced so 

 rank a crop, that it was entirely laid before harvest. The refuse pilchards in Cornwall 

 are used throughout the county as a manure, with excellent effects. They are usually 

 mixed with sand or soil, and sometimes with sea-weed, to prevent them from raising too 

 luxuriant a crop. The effects are perceived for several years. In the fens of Lincoln- 

 shire, Cambridgeshire, and Norfolk, the little fishes called sticklebacks, are caught in the 

 shallow waters in such quantities, that they form a great article of manure in the land 

 bordering on the fens. It is easy to explain the operation of fish as a manure. The skin 

 is principally gelatine ; which from its slight state of cohesion, is readily soluble in water : 

 fat or oil is always found in fishes, either under the skin or in some of the viscera ; and 

 their fibrous matter contains all the essential elements of vegetable substances. 



1 1 33. Amongst oily substances, blubber has been employed as a manure. It is most 

 useful when mixed with clay, sand, or any common soil, so as to expose a large surface 

 to the air, the oxygen of which produces soluble matter from it. Lord Somerville used 

 blubber with great success at his farm in Surrey. It was made into a heap with soil, and 

 retained its powers of fertilising for several successive years. The carbon and hydrogen 

 abounding in oily substances, fully account for their effects ; and their durability is easily 

 explained from the gradual manner in which they change by the action of air and water. 



1 134. Hones are much used as a manure in the neighbourhood of London. After being 

 broken, and boiled for grease, they are sold to the farmer. The more divided they are, 

 the more powerful are their effects. The expense of grinding them in a mill would pro- 

 bably be repaid by the increase of their fertilising powers ; and in the state of powder they 

 might be used in the drill husbandry, and delivered with the seed, in the same manner as 

 rape-cake. Bone-dust and bone-shavings, the refuse of the turning manufacture, may be 

 advantageously employed in the same way. The basis of bone is constituted by earthy 

 salts, principally phosphate of lime, with some carbonate of lime and phosphate of mag- 

 nesia ; the easily decomposable substances in bone, are fat, gelatine, and cartilage, which 

 seems of the same nature as coagulated albumen. According to the analysis of Fourcroy 

 and Vauquelin, ox-bones are composed of decomposable animal matter 51 ; phosphate of 

 lime 37-7, carbonate of lime 10, phosphate of magnesia 1-3 ; total 100. 



1135. Horn is a still more powerful manure than bone, as it contains a larger quantity 

 of decomposable animal matter. From 500 grains of ox-horn, Hatchett obtained only 

 1 *5 grains of earthy residuum, and not quite half of this was phosphate of lime. The 

 shavings or turnings of horn form an excellent manure, though they are not sufficiently 

 abundant to be in common use. The animal matter in them seems to be of the nature 

 of coagulated albumen, and it is slowly rendered soluble by the action of water. The 

 earthy matter in horn, and still more that in bones, prevents the too rapid decomposition 

 of the animal matter, and renders it very durable in its effects. 



1136. Hair, woollen rags, and feathers, are all analogous in composition, and princi- 

 pally consist of a substance similar to albumen united to gelatine. This is shown by the 

 ingenious researches of Hatchett. The theory of their operation is similar to that of 

 bone and horn shavings. 



1 1 37. The refuse of the different manufactures of skin and leather form very useful 

 manures ; such as the shavings of the currier, furriers' clippings, and the offals of the 



