Wisconsin State Agricultural Society. 317 
impregnated with organic acids, derived from the humus, and are 
known as “sour soils," and are unfit for the growth of the cereals 
or the better class of grasses until this property is corrected. 
Others still are so largel} r composed of vegetable matter, that they 
do not possess the requsite amount of mineral matter. The best 
indication of the nature of the soil is the vegetation that natur¬ 
ally grows upon it. 
It is eminently worthy of notice, that our soils are magnesian. 
This, I believe, in the future upholdings of agricultural science, will 
be found to be a very important fact. Magnesia has been a much- 
abused element. It was formerly supposed that magnesian lime¬ 
stone made an inferior quick-lime, and it long lay under disfavor. 
But experience has finally shown that precisely the opposite is true. 
It is far superior to pure limestone for mortar. This is one thing 
that gives to Wisconsin its superiority. Our magnesian limestones 
rank among the very purest known, and will be more esteemed the 
more they are known. It was long supposed to be a useless ingre¬ 
dient as a flux for iron, but it is now becoming apparent that a cer¬ 
tain proportion of magnesia is an advantage. Quick-lime, burned 
from magnesian limestone was formerly prohibited as a fertilizer, 
but the ban has recently been removed. That some such revolution 
of opinion must take place in reference to its utility as an ingredient 
of the soil, is more than probable. If you will examine all the 
analyses of grains, fruits, etc., given by Professor Johnson in his ex¬ 
cellent work, “How Crops Grow, 11 you will find that in the grains, 
magnesia largely predominates over lime, being sometimes five times 
as much. In the woody portion of the plant, however, the reverse 
is the case, the lime is usually double, or more than the magnesia. 
These are very significant facts, and seem to show that magnesia has 
more to do with forming the grain, and lime with forming the fibre 
of the plant. And this suggests forcibly the question, is not the 
well-known superiority of Wisconsin wheat due to this element of 
the soil? 
With the exception of the silicious sandy soil, it would be diffi¬ 
cult to find seven classes of soils more durable and fertile, and more 
easily cultivated than the foregoing. I have said little as to vege¬ 
table mould, because rich as it is in all this region, it is only of 
temporar}' value. It will soon be exhausted by cropping. [ have 
only called attention to those features in the constitution of our 
