He's been trying to perform this ritual every four hours – the objective being to see if there's anything to the rumor that the North Atlantic is striped with currents of warm water. He can present the data to the Royal Society if-God-willing-he-reaches-London. At first he did it from the upperdeck, but he didn't like the way the instrument got battered against the hull, and he was wearied by the looks of incomprehension on the sailors' faces. The old gaffers back here don't necessarily think he's any less crazy but they don't think less of him for it.