AtDTdA (9): 244

[Monte Davis]

> Rays, boys, rays
> Rays of sunlight: an idealized narrow beam of light
> 
> See p. 252: energetic rays
> See p. 258: Vibrational rays
> See p. 445: Quaternian-ray weapons

AtD is set in a ray-crazy era, when even as radio was approaching usefulness
we were still recognizing other wavelengths for the first time

http://en.wikipedia.org/wiki/X-rays

Given that [what we now categorize as] particle beams had some ray-like
behaviors

http://en.wikipedia.org/wiki/Cathode_rays

And that Becquerel's radioactivity included emission of both particles and
gamma rays

http://en.wikipedia.org/wiki/Gamma_ray

It took a while to sort things out, with some pathologies of discovery along
the way 

http://skepdic.com/blondlot.html