100 THOROUGH-DRAINING. 



starved, and the plants it contains frequently perisli, or, as 

 is the case with wheat, lose their hold, and are thrown out 

 by frost. By draining- thoroughly we make the rain our 

 friend and not our enemy, we take all the benefit and avoid 

 the injur}'. It is not, however, only during- winter that 

 superabundant moisture in the land is pernicious, its effects 

 are equally injurious in the drox^g'ht of summer: we see the 

 strong- soils, which in winter were saturated with water, in 

 the droug'ht of summer become hard, impervious, and un- 

 manag-eable, cracked it may be with large fissures, but baked 

 tog-ether so as to exclude all the beneficial infiuences of the 

 atmosphere. The same efiTect is produced in hard frost : let 

 any man attempt to push his walking'-stick into such land at 

 such a time, and he finds it bound in a coat of iron, while 

 that which had been rendered dry and friable by draining- is 

 still loose and pervious. One obvious efiect of water lodging* 

 in the soil, is the exclusion of air; but as the water is drawn 

 off by draining-, the air immediately takes its place, and, in- 

 termixing- with the particles of the soil, communicates to it 

 that divisibility and mellowness to which farmers g'ive the 

 term of " friability." It is from the admission of atmo- 

 spheric air to a g-reater depth, charg-ed as it always is with 

 some deg-ree of moisture, that dry and loamy land is found 

 to resist drought better than wet and adhesive clays. [Mr. 

 Grey then went into a curious and interesting- dissertation on 

 the principle of atmospheric pressure, showing- its effects on 

 all external objects, its tendency to insinuate air into the 

 g-round and occupy the place of water, and even aid in 

 expelling- it; and illustrated its effects as needful to the 

 human Itody, by relating- a circumstance which occurred to 

 the celebrated travellers Humboldt and Bonpland, who, 

 when taking- observations at a great elevation on the 

 Cordillera Mountains, found the air so rarefied as to make 

 breathing- painful, and at leng-th to cause the blood to flow 

 from their eyes and ears, the external pressure being- no long-er 

 equal to counteract the internal impetus of the heart. Apolo- 

 g'izing- for the dig-ression, Mr. Grey proceeded]. Having- said 

 thus much on the utility of draining-, allow me now to make 

 some remarks upon the mode of carrying- it into effect. The 

 first thing-, and that is of essential importance in setting- out 

 drains, is to secure a clear outfall for the water which is to be 

 discharg-ed from them. I have seen much injury and loss sus- 

 tained by allowing- the drainage of a field to be emptied into an 

 open ditch with little declivity, Avhile by neglig-ence in allow- 



