Correspondence between Rita Hinden, Marjorie Nicholson, and Rev. H.M. Grace, Conference of Missionary Societies in Great Britain and Ireland, concerning (i) mining taxation in Sierra Leone and (ii) a meeting with Dr Walter Lowdermilk, American agriculturalist, soil chemist and geologist. Also, an account of Dr Lowdermilk's work and publications (fols. 65-64), and an outline of the Lowdermilk-Africa Project (fols. 65-67).