592 A GRICUL TURE. 



to flow like water, if made hot enough, and the dry sand, mixed 

 with other things, and heated to a high degree, flows off as 

 glass, and gets still harder in cooling. The soils which cover the 

 hard, rocky framework of the earth have been formed in many 

 ways. The hard rocks have been ground up by ice, frost, and 

 snow, dissolved by water, and carried by it from place to place, 

 until nearly the whole earth is covered with this softer covering, 

 in which plants and trees can grow. The decay of these trees 

 added other substances, which did not before exist in the soil, 

 and thus a larger growth was made, the decay of which still 

 further added to the soil. It is this soil, made up of this mix- 

 ture of mineral substances from the rocks, and vegetable decay 

 drawn from the air, which we have to do with in farming. The 

 soil, then, is a great mixture of many substances, and is very 

 different in one locality from that which is found in another. 



Plants. The many kinds of plants which the farmer grows 

 for the purpose of harvesting from them his crops, are the most 

 important things connected with his work. Let us see, then, 

 what we can learn of the ways in which plants get their food, 

 make their growth, and mature their seeds. 



Plants, like animals, are living beings. We do not know ex- 

 actly what this thing we call life is, but we can easily tell a dead 

 animal or a dead plant ; that is, we know when life is there and 

 when it is gone. If we take a powerful microscope, we will find 

 that the water of our ponds and ditches is full of living things, 

 which we cannot see with our naked eye. Many of these we 

 can see are animals, and many others we can see plainly are 

 plants. And then we find some that we cannot be positive as 

 to whether they are animals or plants. But we see that they 

 are living and growing, and we find, in these very minute forms, 

 some which are so small that 150 of them, placed end to end, 

 would only make a line the thickness of the paper this is printed 

 on. We find, then, that there is, in these small things, all of 

 which have life, no distinct line between animal life and vege- 

 table life. We conclude, then, that life in plants and life in 

 animals is the same thing, only it shows itself in different ways, 

 as the plants and animals get larger and better developed. The 

 great oak tree of the forest has life just as our bodies have, but 

 it manifests itself in a different way. The plant, then, is a living 



