HIGH FARMING. r,o:, 



tion is, before manures and every thing else, How can we rem- 

 edy this difficulty? By drainage in the lowlands, and some 

 dressing for the uplands that will condense moisture and retain 

 manures. Every evil in nature has its remedy. Not only can 

 we make our peaty lowlands fertile as gardens by drainage, 

 but this very peat is the true regenerator of your sandy soils, 

 together with the after-application of carboniferous manures 

 and kelp. 



I will not detain you by a description of the process of evap. 

 oration and its effects upon the matter whence the water is 

 taken away, nor make any explanations to fix these facts in your 

 minds; for the following comparison between a solid substance 

 like a brick, and a loose one like peat, will tell the whole story. 

 Take a brick and a mass of peat of equal weight and dryness 

 and get them equally hot. The brick is very close, and will 

 hold its heat a long time, as you know ; the peat is loose, and 

 will soon lose it by radiation ; the structure of peat allows the 

 cold air to enter freely where it will become warm, and it will 

 then rise and give place to colder air from above ; nor, from 

 the equilibrium of things, can it get warm without taking a pro- 

 portionable amount of heat from the peat. Now, as you know, 

 the air always has some moisture in it, and, when it is perfectly 

 full, will deposit it as rain. 



The capacity of air to hold water depends on how hot it is ; 

 for, if you put a dish of cold water in with hot air, it becomes 

 steam, and by some invisible means is conveyed out of the dish 

 and out of sight. The air which was filled partly with moisture 

 now has just as much more in it than before the water evap- 

 orated as the bulk of the water was. But, as you know, when 

 air is subjected to heat it expands, so that our heated air might 

 have been of much less compass once, and by cold may be again, 

 If, then, we bring it into connection with a cool body, the par- 

 ticles of air will become cooled, reduced in volume, and unable 

 to retain the same amount of moisture as before, and will there- 

 fore deposit it upon this cool substance. This is the proi 

 of every summer night. The earth cools by radiation, or evap- 

 oration; the air next to it becomes cool and unable to retain 

 its moisture, which it deposits upon the surface as shown. 



By following me through these steps, you have Been why the 



04* 



