On Mon, 06 Mar 2017 20:10:21 -0800, Jeff Liebermann
wrote:

On Mon, 6 Mar 2017 16:57:41 +1100, James
wrote:

What if I don't want to play with batteries?

Then play with calcium carbide (produces acetylene gas) instead:
https://www.google.com/search?q=acetylene+bicycle+lamp&tbm=isch

Ahem! I don't think you should suggest acetylene gas devices to some
of the folks here. After all the safe limit for acetylene gas is 15
psi, above which it tends to go BOOM! :-)

(but maybe if you wear a helmet and have a bright light... :-)
--
Cheers,

John B.