A short puff of wind extinguished the candle I was carrying. Laying it carefully down at my feet so that I could easily find it again in the dark. I quickly went through my pockets to see if I still had the box of matches which I had thoughtfully put there that morning when I set out to explore the cave. But a thorough search revealed nothing with which to re-light the candle and left me desperately trying to recall how the matches could have gone astray.
I then remembered that, half an hour before I had taken a short rest and eaten a bar of chocolate. While doing so, I had rested the candle on a convenient rock in order to leave my hand free to unwrap the chocolate, and just as now, a breath of wind had made the candle flicker and finally go out. It was then that I had the occasion to use my matches and I can only suppose that I had thoughtlessly felt the box on the rock where the candle had been standing. I reckoned that I must be about half a mile from the entrance and that the only thing for it was to grope my way back again. About an hour later, bruised from my frequent collisions with projecting rocks. I stumbled into the daylight. The first thing I thought of was a cigarette. Instinctively, l drew out my lighter from my trouser pocket. It was only when I had it in my hand that I realized what a fool I had been.
```"The only thing for it" means