ENGLISH AGRICULTURE. 37 



moisture. It dries very slowly, it gives a coolness to the 

 soil which helps, perhaps, more than any other constituent 

 to make it a wholesome home for the roots of plants. This, 

 perhaps, we will be more thoroughly convinced of if we burn 

 off, as we readily may, the organic matter in a soil. We will 

 then find what a loose, sandy, unpromising material is left. 

 The mechanical action of humus makes a soil a comfortable 

 home for roots to live in and to search for their pabulum, 

 and that is not the least important of its uses. Garden soils 

 are proverbially rich, and they abound in vegetable matter. 

 If I were asked for a good broad indication as to fertility of 

 soil, I should say, " Look at its colour." I prefer a brown, 

 dark-coloured hazel loam. The blackness or hazel colour is 

 due to organic matter. So, we see, organic matter is of great 

 importance, though not of the absolute importance which the 

 older chemists attached to it. They thought that humus 

 was the very key to fertility, but Liebig demolished the 

 humus theory some forty years ago. He showed clearly that 

 humus might be regarded rather as a consequence of fertility 

 than as a cause. Liebig rode his hobby too hard. It was 

 left afterwards to others to point out that, while it is true 

 that organic matter is rather an indication of fertility than 

 a cause, yet it is a cause, and a very potent cause, of fertility 

 in soils. 



Lastly, in this particular connection, we come to stones and 

 the coarser and finer mineral fragments. I asked the ques- 

 tion in the most recent examination of the Science and Art 

 Department, "Are stones useful in soils, and why?" I was 

 in several cases answered with a categorical " Yes," or " No." 

 Others told me that stones were useless in soils, because " the 

 seed tumbled from one stone to another, so that it got so 

 deep that it could not get up again ! " 



I Now, mineral fragments are useful in the soil. They are, 

 is has been already pointed out, of all sizes, from microscopic 



