So what happens is that each of the five tubes near the top is spring-loaded, and you push one down and load an ammonia absorber into it. Then you do that for the other four. Guy previously hooked this up to his laptop and programmed in for the thing to work so that each tube was open for a couple hours before closing again, giving five samples over the course of a day. Also key was that at that point we had to go and change the absorbers and it would hopefully be low tide. The tide charts were consulted and Guy programmed his contraption to be timed with the tides as well.
So off we went at low tide, which was of course quite late at night when all the good people of the world should have been asleep. At the cave entrance Guy got the thing out and ready to go.
All true. It wasn't unclimbable due to the structure of the cave or it being too high. Depending on which direction you are reading my blog you either know why, or the next post will answer exactly that question.