Dr. Klaus Volkamer and Hans Heinrich Landolt (* 5. Dezember 1831 in Zürich; † 15. März 1910 Berlin-Wilmersdorf) have measured mass-increase in adsorption processes and chemical reactions.
In his books Dr.Volkamer describes weighing evacuated, silverlined glasbulbs on a precision-scale for several weeks. the precision of the scale was 1/2 000 000 g the weight-increase was in 10 mg range.
His interpretation: dark matter is collected on the phase boundary between glas and silver, or other types of phase boundaries.