Imagine my reaction when Horace handed me the puzzle and I figured out the theme answers. Authors' initials as chemical symbols is a dream come true for a library scientist such as myself. My number 1 was 58A. "The Island of Dr. Moreau" author, to a chemist? (MERCURYWELLS). The book is very good: super creepy and a real think piece. Read it if you haven't yet. I am guessing that 43A. "The Children of Men" author, to a chemist? (PALLADIUMJAMES) is a tribute to the recently departed novelist.
There were a number of other nice clues that tied in with the science theme. 44D. What gallium will do at about 86 degrees F (LIQUEFY), for example. I particularly enjoyed 25D. Notable current researcher (TESLA). A real joule.
49A. Highly draftable ... or a feature of the word "draft" (ONEA) has a
nice seasonal ring to it for me as it's what we hear Mr. Potter saying
over and over again in "It's a Wonderful Life" as he reviews draft
registration papers. I also like any reference to NED Flanders (72A. TV
neighbor of Homer).
Huygens probably liked 41A. U.S. island with a royal palace (OAHU). Also, 9D. BVDs, e.g. (DRAWERS) supplied a little traditional Huygens material. He might have also chuckled at the answer to 6D. Followed up after recon (DEBRIEFED). I know I did.
I don't have much to say about the rest of the puzzle. I only see the early-in-the-week puzzles periodically, so I don't know if the fill is usually this elementary. Most of it seemed Rn of the mill to me.
Ta for now.
Bonus thematic material:
Want to hear a joke about sodium? Na.
How about a joke about potassium? K!