Cavechat.org

http://www.karstportal.org/FileStorage/Texas_Caver/1973-v18-n06.pdf

All the old issues are here, but this one has an article by Jim Jasek on the device he created to calculate Guide Numbers. I think I sent mine to Nathan in Huntsville a couple of years ago.

It is good reading of caving 40 years ago. I was so young then. :)

Phil, Thanks for posting this. You sent a couple to me, too! Still have them.

Well, I knew I sent it to someone in Huntsville. :)

Jim's article is an excellent primer for any new cave photographer. Even after 40 years it is all still relevant info.