Complex sentence: Much of Distant's early life was spent working in a London tannery, and whilst thus employed he made two long visits to the Transvaal which resulted firstly in the publication of "A Naturalist in the Transvaal" (1892).
Split into simpler sentences: Much of Distant's early life was spent working in a London tannery, and while employed there he made two long visits to the Transvaal. The first resulted in the publication of "A Naturalist in the Transvaal" (1892).