A short letter with some key points about effectively learning.
The goal: teaching others.
This can be accomplished in a number of ways: a formal lecture or presentation where many can listen but few can engage in dialogue. Reading & writing letters, which is very asynchronous and takes times. Then there is one-on-one mentorship and dialogue, or quiet conversation, as the letter is entitled.
when the aim is to make a man learn, and not merely to make him wish to learn, we must have recourse to the low-toned words of conversation.
And further, he writes,
we do not need many words, but, rather, effective words.
Words should be scattered like seed; no matter how small the seed may be, if it has once found favourable ground, it unfolds its strength and from an insignificant thing spreads to its greatest growth. Reason grows in the same way; it is not large to the outward view, but increases as it does its work.