86 THE BEGINNER'S GARDEN BOOK 



It is plain that the sandy loam, being the coarsest, has the 

 fewest soil particles, and that the clay loam has the most. 

 Suppose you try drying out the finest of the mud : it becomes 

 a very fine dust. To count the particles of this dust, or even 

 of the sand, would be a very difficult task, yet it has been 

 attempted. The conclusion was that a gram (that is, less 

 than a third of an ounce) of sandy loam contains about two 

 billion soil particles. This number increases steadily as the 

 loam grows finer, until the clay loam sometimes contains 

 twenty billion particles per gram ! 



But we are far from finding all the important parts of the 

 loam. Sand, silt, and clay are very important, but we must 

 not forget those particles, more or less water-soaked, which 

 we saw floating in the water. Let us examine the tumbler 

 containing the fine clay, or the coarser silt. As we look 

 down into it we see that the layer at the bottom is by no 

 means made up of little particles, all small and round. 

 Here and there, in fact quite plentifully, we shall see what 

 seem to be little short hairs, or the tiniest of sticks, bent or 

 crooked, lying among the rock particles. These are not made 

 of minerals. No, they were once alive, are bits of roots or " 

 leaves, which have rotted in the soil. "Decaying vegetable 

 matter," or "humus," — that is what we have discovered. 



Those floating things in the water are of the same sort, 

 but not yet so rotted as to be waterlogged. And the dirty 

 water is the soil water to feed the plants, with the very tiniest 

 of particles still suspended. 



But did we pour away all the water ? Take some of your 

 silt and stir it in the sun, or heat it over a fire. It grows 

 lighter in color, and you know why. It is drying out. 

 Water, then, is present in every garden, clinging to each 

 particle. In fact, every tiniest particle of soil is coated with 

 a film of water. 



