He was assistant-surgeon to the Colony of NSW, under White, at its inception. He was one of the few British officers who investigated the natural history of the place. He writes to Banks, under date, Port Jackson, 18th November, 1788, sending various zoological specimens. He also sends herbarium specimens, Grass-tree gum, and speaking of the "large Peppermint tree," (Eucalyptus) says, "if there is any credit in applying these and many other simples to the benefit of the poor wretches here, I certainly claim it, being the first who discovered and recommended them."
Secretary of State Dundas wrote," 14th ,July, 1792, granting leave of absence to Considen to return to England should thle state of his health continue to require it. I know nothing further concerning this worthy.
In commemoration of this pioneer work with Eucalyptus I have dedicated Eucalyptusi consideniana to his memory.
See also Hall 1978
Source: Maiden, J.H. (1908) Records of Australian botanists- (a) General, (b) New South Wales. Journal and Proceedings of the Royal Society of New South Wales for 1908. 42:60-132