William), younger brother of the preceding, born at Lenthe, Hanover; like his brother took to science, and in 1844 settled in England, naturalising in 1859; was manager of the English branch of the Siemens Brothers firm, and did much to develop electric lighting and traction (Portrush Electric Tramway); his inventive genius was productive of a heat-economising furnace, a water-meter, pyrometer, bathometer, &c.; took an active part in various scientific societies; was President of the British Association, and received a knighthood in 1883 (1823-1883).