Lawrence Hargrave (1850-1915): 1896 use of NSW 1½d Letter Card headed 'Stanwell Park/Clifton' & signed 'Law Hargrave, Hargrave was a world-renowned researcher into the principles of flight. He was also an early explorer of British New Guinea, and had other scientific interests including astronomy. His country home was 'Hillcrest House' at Stanwell Park. He was commemorated on a 1965 5d stamp & on the initial $20 banknote. Hargrave's letter is to early stamp dealer William Petterd, but in respect of a book about Tasmania's minerals.