Independent 6546 / Virgilius – It’s rocket science!

Solving Time:  17 minutes

Another breathtaking puzzle from Virgilius, who is surely in the elite of setters. 
The clues are all thematic, concise, read splendidly and bring a smile to the face
(Especially 14/18 across!!).

As always, a shining example to aspiring setters that the most obvious can be
hidden in a beautiful clue.

ACROSS   * = ANAGRAM  /  CD  =  CRYPTIC DEF / R = REVERSAL

1 CHARGE  Triple definition all science related!
5 PARALLAX PAR + A L (a line) + LAX
9 BUTANE  BUT + A + NE (neon)
10 TITANIUM (IT + A MINUT (Less than a minute!!)*
11 HEIGHTEN EIGHT inside HE + N
12 LASER  The only clue to cause me some concern –  This looks like
   a homophone for LAZER, one who lazes.
14/15 PERIODIC TABLE OF THE ELEMENTS Stunning!  He is Helium (element number 2) and I (Iodine) is no 53.
18 MESON  Hidden answer
19 NICHROME (IRON + CHEM)*
22 PURIFIER PURI + FIRE*
23 APOGEE  A P + OGEE (a curve)
24 GEOMETRY GEO (George) + ME + TRY (Experiment)

DOWN
2 HOUSE  2 Defs
3 REALGAR  Hidden answer
4 ELECTRODES D in STEEL CORE*
6 RATS  As used by Charlie Brown!  Dbl def.
7 LINEAR B A in LINER + B
13 ATOMIC MASS Nice cryptic def
14  PROCEDURE REPRODUCE*
16 THORIUM  HOT* + I in RUM
17/25 NERVOUS SYSTEM RUNS MESSY VOTE*
21 GILT  Initial letters

Bravo Virgilius!