Historical clue formulations

• Like atoms vis-à-vis molecules — 2021-04-27
• Requiring greater magnification — 2014-01-17
• More minute — 2008-09-04
• More 26-Across — 2008-04-10
• More diminutive — 2005-05-16
• Harder to make out, maybe — 1999-12-18
• Like the bottom of an eye chart, comparatively speaking — 1995-08-26