It may be well at times to use words of a more difficult or scientific character; but these should always have the proper explanation given; the words used most frequently in common life, in ordinary and proper conversation, ought to be most strongly impressed on their memories.

It may, perhaps, be retorted on me--why then teach the difficult and scientific names of geometrical figures.

The answer is very simple.

Most of them have no other, and where they have I always give them also, as sloping, slanting, inclined, for oblique.
The geometrical figures are the elements of all forms, and the simplest objects which can be presented to the young.

I have found them always learned with the greatest ease and pleasure.