Wisconsin State Agricultural Society. 
311 
Here are some pieces of quartz rock. I broke off pieces from 
these and ground them in a mortar until they were reduced to 
small grains, and here you see we have a silicious sand. But I 
continued to grind a portion until it became a fine powder and 
this when wet gave this clay-like mass, this of course is silicious 
like the other. 
Here is a piece of limestone which was subjected to the same 
process, and here we have a sand again, but of course a calcareous 
one. A portion ground still finer, gave this clay-like mass, very 
similar to the former, but calcareous. 
Here again is a rock containing feldspar, a common mineral which 
contains a large proportion of alumina, and by appropriate processes 
common alum could be made from it; hence, we speak of its pro¬ 
ducts as aluminous sand, as you see, and by reducing it still further 
we have a true aluminous clay. If we had stopped the grinding 
process in any of these cases midway between the sand and the very 
fine powder, we should have obtained a loamy material, but in the 
one case it would have been silicious, in another calcareous, and in 
a third aluminous. It is evident then, that to say that a soil is sandy, 
loamy, or clayey, is saying very little as to its chemical nature or 
its fertility. Let us now apply to these a very simple test. 
Here is some hydrochloric or as it is commonly termed muriatic 
acid. Let us drop into it the sand we manufactured from the quartz 
rock, and which we called silicious, and you see no evidence of chem¬ 
ical action. Let us now add some of the aluminous sand, made 
from the feldspar, and still we see no action. But now as we pour 
in some of the calcareous sand, made from the lime stone, you see a 
brisk effervescence. 
We will repeat the test with the clay-like masses and we have 
similar results, so that, so far as these three substances are concerned, 
we may distinguish the calcareous material from the others by this 
simple test. By similar appropriate meaus, we may distinguish all 
the substances that enter into the composition of the soil; but these 
three substances are, by far, the most common ingredients in our 
soil, and so have been dwelt upon. But I ought to say that this 
limestone, and that throughout the eastern part of the state, con¬ 
tains a large portion of magnesia. 
If you have been kind enough to follow me through this explan¬ 
ation, made necessary by the looseness of common terms, we shall 
