The Littlemore clock, by E.T.Hall is documented in Derek Roberts’ book:
Precision Pendulum Clocks: France, Germany, America and recent advancements.
In this article the author blames a chestnut tree for causing fluctuations
to his clock. He shows in his data, the effects of wind on time keeping.
However, it is difficult to separate the air pressure effects from the seismic
interference with the pendulum through the ambient gravity. And the chestnut tree may
have been innocent as the effect may have been ground seismic fluctuations on a larger scale.
The turbulent eddies in the atmosphere involve masses of air in the order of cubic kilometres,
with temperature contrasts that cause density differences and consequent mass movements.
There are not many good barometric sensors, but even fewer sensitive gravity
sensors.
I saw an article, years ago, about a down borehole gravity meter using a vibrating wire
supporting a weight. I have thought of constructing a gravity meter using a tungsten wire
supporting a tungsten weight, vibration of the wire being sustained electrostatically.
The bottom line, though, is that these are all oscillations about a mean, and the mean
stays quite constant over a long period of time.
Cheers,
Neville Michie