In 1881 Eccles befriended T. G. Bonney, an alpinist of some repute and professor of geology at University College, London. Eccles provided photography for Bonney's geological volume The Building of the Alps, and accompanied him on trips to the Alps that provided material for Bonney's paper On the Crystalline Schists and their Relation to the Mesozoic Rocks in the Lepontine Alps. Bonney wrote Eccles's obituary in the Alpine Journal.