ation of all experience by
uniting its parts into groups and series. The smith, in welding
together two pieces of iron, heats both and then hammers them together
into one piece. The teacher has something similar to do. He must
revive old ideas in the child's mind, then present the new facts and
bring the two things together while they are still fresh, so as to
cause them to coalesce. To prove this observe how long division may be
best taught. Call up and review the method of short division, then
proceed to work a problem in long division calling attention to the
similar steps and processes in the two, and finally to the difference
between them.

The defect of much teaching in children's classes is that the _teacher_
does not properly provide for the welding together of the new and old.
The important practical question after all is whether instructors see
to it that children recall their previous knowledge. It is necessary
to take special pains in this. Nothing is more common than to find
children forgetting the very thing which, if remembered, would explain
the difficult point in the lesson. Teachers are often surprised that
children have forgotten things once learned. But, in an important
sense, we encourage children to forget by not calling into use their
acquisitions. Lessons are learned too much, each by itself, without
reference to what precedes or what follows, or what effect this lesson
of to-day may have upon things learned a year ago. Putting it briefly,
children and teachers do not _think_ enough, pondering things over in
their minds, relating facts with each other, and bringing all knowledge
into unity, and into a clear comprehension. The habit of
_thoughtfulness_, engendered by a proper combining of old and new, is
one of the valuable results of a good education. It gives the mind a
disposition to glance backward or forward, to judge of all old ideas
from a broader, more intelligent standpoint. Thinking everything over
in the light of the best experience we can bring to bear upon it,
prevents us from jumping at conclusions.

The general _plan of all studies_ is based upon this notion of
acquiring knowledge by the assistance of accumulated funds. In
_Arithmetic_ it would be folly to begin with long division before the
multiplication table is learned. In _Geometry_, later propositions
depend upon earlier principles and demonstrations. In _Latin_,
vocabularies and inflections and syntactical