Amplify, v. i.
1. To become larger. [Obs.] Strait was the way at first, withouten light, But further in did further amplify. Fairfax.
2. To speak largely or copiously; to be diffuse in argument or description; to dilate; to expatiate; -- often with on or upon. Watts. He must often enlarge and amplify upon the subject he handles. South.
1 other Webster entry under this spelling
Amplify, v. t. [imp. & p. p. Amplified; p. pr. & vb. n. Amplifying.]
1. To render larger, more extended, or more intense, and the like; -- used especially of telescopes, microscopes, etc.
2. (Rhet.)
To enlarge by addition or discussion; to treat copiously by adding particulars, illustrations, etc.; to expand; to make much of. Troilus and Cressida was written by a Lombard author, but much amplified by our English translator. Dryden.
Shades of meaning
Amplify is now rarely used in the sense of increase, to add material substance, bulk, volume, or the like; it is now almost wholly applied to discourse or writing, signifying to make fuller in statement, whether with or without adding matter of importance, as by stating fully what was before only implied, or by adding illustrations to make the meaning more readily apprehended, etc. The chief difficulty of very young writers is to amplify, to get beyond the bare curt statement by developing, expanding, unfolding the thought. The chief difficulty of those who have more material and experience is to condense sufficiently. So, in the early days of our literature amplify was used in the favorable sense; but at present this word and most kindred words are coming to share the derogatory meaning that has long attached to expatiate. We may develop a thought, expand an illustration, extend a discussion, expatiate on a hobby, dilate on something joyous or sad, enlarge a volume, unfold a scheme, widen the range of treatment.
Prepositions
To amplify on or upon the subject is needless. Amplify this matter by illustrations.