200 SCIENCE IN SHORT CHAPTERS. 



year land so reclaimed will yield remunerative crops." And 

 further, that " after being broken up a second time the land 

 materially improves, and becomes doubly valuable." Also 

 that he has no doubt that " all bog-lands may be thus re- 

 claimed, but it is up-hill work, and not remunerative to attempt 

 the reclamation of bogs that are more than four feet in depth." 



There is another and a simpler method of dealing with bogs 

 viz. setting it into narrow ridges ; cutting broad trenches 

 between the ridges ; piling the turf cut out from these trenches 

 into little heaps a few feet apart, burning them, and spreading 

 the ashes over the ridges. This is rather largely practised on 

 the coast of Donegal, in conjunction with sea-weed manuring, 

 and is prohibited in other parts of Ireland as prejudicial to the 

 interests of the landlord. 



We shall now proceed to the philosophy of these processes. 



First, the drainage. Everybody in Ireland knows that the 

 bog holds water like a sponge, and in such quantities that ordi- 

 nary vegetation is rotted by the excess of moisture. There is 

 good reason to believe that the ancient forests, which once oc- 

 cupied the sites of most of the, Irish bogs, were in some cases 

 destroyed by the rotting of their stems and roots in the excess 

 of vegetable soil formed by generations upon generations of 

 fallen leaves, which, in a humid climate like that of Ireland, 

 could never become drained or air-dried. 



But this is not all. There is rotting and rotting. When the 

 rotting of vegetable matter goes on under certain conditions it 

 is highly favorable to the growth of other vegetation, even of 

 the vegetation of the same kind of plants as those supplying 

 the rotting material. Thus rotten and rotting straw is a good 

 manure for wheat ; and the modern scientific vine-grower care- 

 fully places the dressing of his vines about their roots, in order 

 that they may rot, and supply the necessary salts for future 

 growth. The same applies generally ; rotting cabbage leaves 

 supply the best of manure for cabbages ; rotting rhubarb leaves 

 for rhubarb ; rose leaves for rose trees ; and so on throughout 

 the vegetable kingdom. 



Why, then, should the bog - rotting be so exceptionally 

 malignant ? As I am not aware that any answer has been given 

 to this question, I will venture upon one of my own. It ap- 

 pears to be mainly due to the excess of moisture preventing 

 that slow combustion of vegetable carbon which occurs wher- 

 ever vegetable matter is heaped together and slightly moist- 

 ened. We see this going on in steaming dunghills ; in hay- 



