The old idea of a librarian was that of a guardian or keeper of books—not a diffuser of knowledge, but a mere custodian of it.
Never fear that you can be too prolix: the diffuser you are, the easier I shall forgive myself.
The most conspicuous addition made by Mr. Boyden was the diffuser.
It seems probable that he was a diffuser of knowledge rather than an originator, but as a great teacher his fame is secure.
Here is an example of Spenser's diffuser style, taken from the second book of the Faerie Queene.