18 HOW CROPS GROW. 
ging, planting, manuring, and irrigating, had their suffi- 
cient reason for every step. In all cases, thought goes 
before work, and the intelligent workman always has a 
theory upon which his practice is planned. No farm 
was ever conducted without physiology, chemistry, and 
physics, any more than an aqueduct or a railway was ever 
built without mathematics and mechanics. Every success- 
ful farmer is, to some extent, a scientific man. Let him 
throw away the knowledge of facts and the knowledge of 
principles which constitute his science, and he has lost the 
elements of his success. The farmer without his reasons, 
his theory, his science, can have no plan; and these want- 
ing, agriculture would be as complete a failure with him 
as it would be with a man of mere science, destitute of 
manual, financial, and executive skill. 
Other qualifications being equal, the more advanced and 
complete the theory of which the farmer is the master, the 
more successful must be his farming. The more he knows, 
the more he can do. The more deeply, comprehensively, 
and. clearly he can think, the more economically and ad- 
vantageously can he work. 
That there is any opposition or conflict between science 
and art, between theory and practice, is a delusive error. 
They are, as they ever have been and ever must be, in the 
fullest harmony. If they appear to jar or stand in con- 
tradiction, it is because we have something false or incom- 
plete in what we call our science or our art ; or else we do not 
perceive correctly, but are misled by the narrowness and. 
aberrations of our vision. It is often said of a machine, 
that it was good in theory, but failed in practice. This is 
as untrue as untrue can be. If a machine has failed in 
practice, it is because it was imperfect in theory. It should 
be said of such a failure—the machine was good, judged 
by the best theory known to its inventor, but its incapacity 
to work demonstrates that the theory had a flaw. 
But, although art and science are thus inseparable, it 
