(Humphrey) Thompson Jackson, Esquire

(Per Wm McCully Sep 29, 1821) "Thompson Jackson Esq. of Dublin, unmarrried, who now inherits the estate in Ballyregan aforesaid, which may be worth three hundred pounds a year"

Thompson was elected as a member of the Royal Dublin Society in January 1836. See documents for source (Objects seem to surround natural history)

It is believed he died intestate and without issue, so the estate did not pass to his cousin Thompson Dalzell, aka Humphrey Thompson Jackson Dalzell 1810-1885, which was his wish. (unsourced, unproven)