His personal estate, then worth £750, was insufficient when his will was finally probated in 1891. His heir, a nephew, refused to inherit because he did not want to accept the conditions of changing his own surname to De Moleyns and living for one in every four years in County Kerry. Under the will the money passed to University College, London for purpose of endowing a professorship in electrical science. The funds were insufficient so instead a trust fund, called the De Moleyns Fund, was set up in his memory by the University for the purpose of purchasing electrical equipment.