# A mysterious note in the lab

As I wrapped up another long day of running experiments with only mediocre yields, I prepared to turn off the fume hood and go home. However, before I left, a note caught my eye—my professor had signed it with his name and left it in my locker! Attached is what he wrote on the note. Can you figure out the missing number, and what my professor was trying to tell me?

$$\begin{array}{c|c|c|c} & \mathbf{1 5} & \mathbf{1 6} & \mathbf{1 7} \\ \hline \mathbf{2} & -1.4 & ? & 3.2 \\ \hline \mathbf{3} & 2.1 & -2.8 & -5.9 \end{array}$$

Here's a markdown version:

15 16 17
2 -1.4 ? 3.2
3 2.1 -2.8 -5.9

Hint:

The numbers in the table are physical constants.

Hint 2:

The constants in the table are very particular base-ten logarithms, which are relevant to the theme of the puzzle.

• Are these numbers approximate or exact? Commented May 20 at 8:51
• Well, no physical numbers are exact. Take that how you will. Commented May 20 at 12:14
• rot13(Ner gur ahzoref fbzrubj eryngrq gb cbjref bs gra va fpvargvsvp abgngvba??) Commented May 22 at 12:25
• @Dreopa rot13(Gurl ner eryngrq gb cbjref bs gra va n irel cnegvphyne jnl.) Commented May 22 at 16:13
• I'm not a chemist so before I spend more time looking at wiki pages rot13(ner gur ahzoref eryngrq ng nyy jvgu gur ryrzragf va gur cbfvgvbaf tvira ol gur neenl vaqrkvat va gur crevbqvp gnoyr?) Commented May 24 at 9:16