Historical clue formulations

• Compound with a caret-shaped molecule, as depicted by this puzzle's circled letters — 2026-05-14
• Something well-taken? — 2026-04-05
• With 42-Across, zodiac trio that hints at the longest answers in this puzzle — 2024-05-28
• Zero-calorie beverage — 2023-11-17
• What more than half of the human body is composed of — 2023-08-08
• With 55-Across, no longer an issue — 2022-02-02
• One piece of evidence of a planet's habitability — 2021-09-20
• Word with hold or holy — 2021-05-28
• Something that's well-kept? — 2021-02-21
• Fire extinguisher — 2019-03-24
• Designated driver's order — 2018-10-18
• Word repeated before "everywhere" — 2017-09-12
• Well-kept resource — 2017-03-31
• H20 — 2016-10-17
• With 68-Across, what the groups of circled letters are famous examples of — 2015-08-19
• Tend to, in a way, as a garden — 2015-05-05
• With 7-Down, incapable of leaking — 2015-01-21
• Need for life — 2014-03-15
• Plain dinner quaff — 2014-03-12
• See 31-Down — 2012-07-10
• Tend, as plants — 2011-08-31
• Something well-preserved? — 2011-06-19
• H2O — 2011-03-21
• Firefighting aid — 2011-01-25
• Tend to, as plants — 2010-05-04
• With 104-Down, utility gauge — 2010-01-10
• Marathon handout — 2008-12-30
• See 22-Down — 2008-11-20
• It's in the spring — 2008-06-01
• Pipe contents — 2005-07-10
• It may be well-taken — 2005-03-30
• Use a hose on, as a garden — 2004-07-12
• An element, to the ancients — 2004-01-07
• Addition to a concentrate — 2003-05-20
• It's in the spring — 2003-03-09
• End of the quip — 2000-06-08
• Puzzle's theme (shown in 20-, 40-, 58-Across and 21-Down) — 2000-02-24
• Firefighting need — 1996-12-17
• No-cal drink — 1996-12-06
• Fire fighter — 1996-09-14
• Tend the plants — 1994-12-03
• Spray — 1994-10-08
• See 13-Across — 1994-09-01
• Fire fighter — 1994-07-08