No. 144.] 517 



SO per cent ; but half the quantity of seed will be required, and 

 the farmer will be enabled to double his stock and thus increase 

 the substantial manures Sometimes soils contain one per cent 

 of sulphate of protoxide of iron (or the green vitriol of the shops), 

 a salt which always exerts a very poisonous action upon all 

 plants; many will not grow upon such a soil; by draining and 

 using lime this salt becomes soluble, and finds its way to the 

 drain by percolation. 



Persons who have not had an opportunity of observing the dif- 

 ference between undrained and drained land cannot well judge 

 when land requires drain ige, the following description may be df 

 service to such : When land requiring drains is in course of dry- 

 ing up in summer, the soil cracks in all directions, and the sur- 

 face soon becomes too dry and hard for the growth of plants, and 

 is even diificult to work with spade or plough. When the rains 

 fall these open fissures fill immediately with water, which for the 

 want of an outlet continues in the soil, and renders it wet and 

 totally unfit for successful cultivation. The crops on such a soil 

 in the spring will look sickly and yellow, their parts not being 

 fully developed cause them to grow and ripen unequally, if they 

 come to maturity at all, and they are not apt to, as such a soil 

 has no oxygen in it, absence of which acts precisely the same as 

 a superabundance of carbonic acid would when stagnant water is 

 renewed, the air is renewed to the extent that water contains it 

 in a soluble form. If the water is withdrawn from such a soil, 

 giving access to air, it soon becomes a fruitful and valuable 

 meadow. If an animal is buried in such a soil before draining 

 he does not decay, on account of the absence of oxygen, but 

 putrefies from the action of air contained in him. 



Putrefaction is a deoxidizing process which extends to all 

 bodies, even the roots of trees ; the moment oxygen is extracted 

 from any substance it putrefies. Air is renewed in a soil by fre- 

 quent ploughing, which changes the putrefaction of its organic 

 constituents into a process of oxidation, from which time its ferti- 

 lizing effects increase rapidly, and it is fitted to appropriate in 

 proper quantities carbonic acid gas, water and ammonia, to feed 

 the fully developed plant. 



