in a democracy like ours should be able to exercise his franchise
intelligently; but the citizen who is responsible for the management
of farm lands ought surely to be at least as well informed
concerning the principles which underlie the maintenance of soil
fertility; provided, of course, that such knowledge is within his
reach; and from what you say I am beginning to believe that such is
the case. At any rate this simple test seems to show conclusively
that this soil contains no limestone, and it is common knowledge
that limestone soils are good soils."

Percy took up the ball of soil containing the slip of blue paper,
broke it in two again, and it was seen that the paper had changed in
color from blue to red

"There's a change, for certain," said Mr. West, "that has some
meaning to you I suppose."

"This is litmus paper," said Percy. "It is prepared by moistening
specially prepared paper with a solution of a coloring matter called
litmus, and the paper is then dried. This coloring matter has the
property of turning blue in the presence of alkali and red in the
presence of acid. The blue paper is prepared with a trace of alkali,
and the red paper with a trace of acid. If more than a trace were
present the litmus paper would not be sufficiently sensitive for the
test.

"This little bottle containing two dozen slips of paper cost me five
cents, and it can be obtained at most drug stores.

"Alkali and acid are exactly opposite terms, like hot and cold. The