[elvinyung]

Maybe "he" is short for "Helios" :-)

[OJFord]

Or it's the elemental symbol for Helium, and they knew about nuclear fusion.

Oh, you weren't joking?

[Sharlin]

Well, coincidentally, helium was discovered in 1868, just a few years after the OP article was written, via detection of a spectral line in sunlight that didn't correspond to any previously known element. Hence the name. Of course they didn't yet have any idea about stellar nucleosynthesis and helium's role in it.