Book IV. IMPLEMENTS OF AGRICULTURE. 361 



2371. The deterioration of the British dimate is an idea entertained by somej but 

 whether in regard to general regularity, temperature, moisture, or wind, the alleged 

 changes are unsupported by satisfactory proofs. It is not improbable but the humidity 

 of our climate, as Williams alleges (Climate of Britain, &c. 1816J, has of late years 

 been increased by the increase of evaporating surface, produced by the multiplicity of 

 hedges and plantations ; a surface covered with leaves being found to evaporate con- 

 siderably more than a naked surface. If the humidity of the climate was greater 

 before the drainage of morasses and the eradication of forests for agricultural purposes, 

 a comparative return to the same state by artificial planting and irrigation, must have a- 

 tendency to produce the same results. However, it will be long before the irrigation of 

 lands is carried to such a degree as to produce the insalubrious effects of undrained 

 morasses ; and as to our woods and hedges, we must console ourselves with the beauty 

 and the shelter which they produce, for the increase of vapor supposed to proceed from 

 them. 



BOOK IV. 



OF THE MECHANICAL AGENTS EMPLOYED IV AGRICULTURE. 



2372. Having taken a view of the vegetable and animal kingdoms, as supplying the 

 subjects of agricultural improvement, and of the mineral kingdom, manures, and the 

 weather, as the natural agents of their growth and culture ; our next course is to ex- 

 amine the mechanical agents, or implements, machines, and buildings employed in 

 agricultural operations. In a rude state of husbandry few implements are required be- 

 sides the plough and the cart, and few buildings beside the stable and the barn. The 

 ground is ploughed, and the seed thrown in and covered with a bush ; at harvest it is 

 cut down and carted to the barn ; and the three grand operations of the farmer are 

 sowing, reaping, and thrashing. But in our improved state of society, where all the 

 science of mechanics as well as chemistry, is made to bear on agriculture, the imple- 

 ments, machines, and buildings become numerous, and equally so the operations. So 

 numerous are the former, indeed, that the theoretical enquirer is often puzzled in mak- 

 ing a selection. The wbole of the most improved agriculture, however, may be, and in 

 fact is, carried on with a very limited variety both of implements and buildings : intricate 

 and complicated machines are not adapted for a rustic art like agriculture, and a great 

 variety are not required for an art whose operations are so simple as almost to be uni- 

 versally understood and practised. In our enumeration we shall include a number that 

 we do not consider of much consequence ; but we shall always distinguish between the 

 essential, and such as are comparatively objects of superfluous ingenuity and expense. 

 We shall adopt the or^er of Implements of Manual Labor, Implements or Machines 

 impelled by quadrupeds or other powers, Structures, and Buildings. 



Chap. I. 

 Of the Implements of Manual Labor used in ^Agriculture. 



2373. Though the most important implements of agriculture are drawn or put in 

 action by beasts of labor, yet a few are used bt/ man alone, which cannot be dispensed 

 with. These may be arranged as tools, or simple implements for performing operations 

 on the soil ; instruments for performing operations on plants or animals, or other more 

 delicate operations ; utensils for the deportation of materials ; and hand machines for 

 various purposes. 



Sect. I. Tools used in Agriculture. 



2374. The lever is an inflexible straight bar of iron or wood, employed in connection 

 with a prop or fulcrum, on which it is supported. There are three kinds, but the most 

 common is that in which the fulcrum is between the power and the weight. Its use in the 

 removal of large stones or other heavy bodies is well known, and the advantage of its 

 application depends on the distance of the power from the fulcrum, and the proximity of 

 the weight. 



2375. The pick or mattock consists of two parts, the handle, which ought to be 

 formed of sound ash timber or oak, such as is obtained from the root or butt end of a 

 middle aged tree j and the head, which should be formed of the best iron and pointed. 



