I encountered a gas refrigerator on a trip out West back in 1966 or so. The place we stayed had only recently got AC power so the gas refrigerator made sense. It seemed to be cold and freeze water just like any other refrigerator. Being 9 or 10 years old at the time I was fascinated that a device could be built that could make cold using only a flame. My dad had seen such things before and was not surprised, he told me there were even kerosene refrigerators at one time.
Anyway Google "absorption cycle" if you want to know the history and how it works. Here's one example:Sorry, can't think of any way to tie this back to telecom. Never heard of a gas phone.
Dave Grebe[TELECOM Digest Editor's Note: But I have heard that when a gas leak is suspected, one should _never_ use a telephone in the vicinity as there is a remote chance of a spark hitting the gas and causing an explosion. PAT]