308 SCIENCE OF AGRICULTURE. Part II. 



commonly kept without food for some time, as if killed with ftiU stomachs their flesh is 

 considered not to keep well. Oxen are commonly fasted two or three days, smaller 

 animals a day, but it is evident that the practice must not be carried too far, as the oppo- 

 site effect will be produced by the animal falling off or getting feverish. Dr. Lister has 

 stated that nothing contributes more to the whiteness and tenderness of the flesh of calves 

 than often bleeding them,^ by which the coloring matter of the blood is exhausted, and 

 nothino- but colorless serum remains. A much more cruel method of preparation for 

 slaughter used to be practised, though now much less frequently, in regard to the bull. 

 By some ancient municipal laws, no butcher was allowed to expose any bull beef for 

 sale unless it had been previously baited. The reason of this regulation probably was, 

 that baiting had the effect of rendering the flesh or muscular fibre much more tender ; for 

 it is a universal law of the animal economy that, when animals have undergone excessive 

 fatigue immediately before death, or have suffered from a lingering death, their flesh, 

 though it becomes sooner ridged, also becomes sooner tender than when suddenly 

 deprived of life in a state of health. The flesh of hunted animals also is soon tender and 

 soon spoils {Reckerches de Physiologie et de Chimie Fathologique,par. P. iV. Nysten. 8vo. 

 Paris, 1811.) ; and it is upon this principle only, that the quality of pig's flesh could be 

 improved by the horrid cruelty, said to be practised by the Germans, of whipping the 

 animal to death. 



BOOK IIL 



OF THE STUDY OP THE MINERAL KINGDOM AND THE ATMOSPHERE, WITH REFERENCE 



TO AGRICULTURE. 



2053. The nature of the vegetable and animal kingdom having undergone discussion, 

 the next step in the study of the science of agriculture is to enquire into the composition 

 and 7iature of material bodies ^ and the laws of their changes. The earthy matters which com- 

 pose the surface of the earth, the air and light of the atmosphere, the water precipitated 

 from it, the heat or cold produced by the alternation of day and night, and by che- 

 mical composition and resolution, include all the elements concerned in vegetation. 

 These elements have all been casually brought into notice in the study of the vegetable 

 kingdom ; but we shall now examine more minutely their properties, in so far as they are 

 connected with cultivation. To study them completely, reference must be had to systems 

 of chemistry and natural philosophy, of which those of Dr. Thomson {System of Chemis- 

 try,) axidDr. Young, {Lectures on Natural Philosophy f) may be especially recommended. 



Chap. L 

 Of Earths and Soils. 



2054. Earths are the productions of the rocks which are exposed on the surface of the 

 globe, and soils are earths mixed with more or less of the decomposed organised matter 

 afforded by dead plants and animals. Earths and soils, therefore, must be as various as 

 the rocks which produce them, and hence to understand their nature and formation it is 

 necessary to begin by considering the geological structure of the territorial surface, and 

 the manner in which earths and soils are produced. We shall next consider in succession 

 the Nomenclature, Quality, Use, and Improvement of Soils. 



Sect. I. Of the Geological Structure of the Globe and the Formation of Earths and Soils. 



2055. The crust, or under surface of the earth, is considered by geologists as presenting 

 four distinct series of rocky substances ; the first, supposed to be coeval with the world, 

 are called primitive, and consist chiefly of granite and marble, below which man has not 

 yet penetrated. The second series, called by the Wernerians transition-rocks, are of more 

 recent formation, and seem to have resulted from some great catastrophe, (probably that 

 to which history gives the name of deluge,) tearing up and modifying the former order 

 of things. Clay-slate is one of the principal rocks of this class, and next limestone, 

 sandstone, and trap or whinstone. The third series are called secondary rocks, and 

 seem to owe their formation to partial or local revolutions, as indicated by their compa- 

 ratively soft or fragile structure, superincumbent situation, and nearly horizontal position. 

 They are chiefly limestones, sandstones, and conglomerations of fragments of other rocks, 

 as plum-pudding-stone, &c. and appear rather as mechanical deposits from water than 

 as chemical compounds from fusion or solution. A fourth stratum consists of alluvial or 

 earthy depositions from water, in the form chiefly of immense laeds of clays, marls, or 

 sands These strata are far from being regular in any one circumstance; sometimes one 



