Fridtjof Nansen, Shale Niskin oceanography |
Nansen bottle
Fridtjof Nansen had to wonder whether the seawater was layered— how temperature and salinity varied with depth. He had to wonder and to figure how to get the data. The famous explorer and statesman Fridtjof Nansen combined a reversing thermometer with a bottle, both being triggered by a “messenger weight” to capture temperature and a water sample at a given depth.
Niskin improvements
The Niskin bottle doesn’t need to be rotated to trap a water sample, and is made of plastic to reduce contaminating its sample. Some Niskin bottles are preset to close at a given depth and some are triggered by an electric signal from the surface. Many Niskin bottles may be mounted on a rosette to capture temperatures and samples at many depths.
Not obvious
You had to wonder and the point is people didn’t, which is why one rarely needs to prove it isn’t obvious.
The three main criteria for showing that an invention is can be patented are originality, usefulness, and non-obviousness.
See also in The book of science:
Readings in wikipedia: