We chose some systematic treatise as our text-book; my father's _Elements_ being our first choice.

One of us read aloud a chapter, or some smaller portion of the book.

The discussion was then opened, and anyone who had an objection, or other remark to make, made it.

Our rule was to discuss thoroughly every point raised, whether great or small, prolonging the discussion until all who took part were satisfied with the conclusion they had individually arrived at; and to follow up every topic of collateral speculation which the chapter or the conversation suggested, never leaving it until we had untied every knot which we found.

We repeatedly kept up the discussion of some one point for several weeks, thinking intently on it during the intervals of our meetings, and contriving solutions of the new difficulties which had risen up in the last morning's discussion.