Boston directory, 1865 through 1872.
M. F. Sweitser, King’s handbook of Newton, Massachusetts, Boston, Mass., 1889, p. 203.
Smith, op. cit. ([footnote 22]), p. 20.
The sources used were Crossman, op. cit. ([footnote 8]), December 1887; Henry G. Abbot, Watch factories of America, Chicago, 1888, pp. 93-95; Newton directory for 1875, 1877, 1879, 1881, 1883, 1884-85, and 1885; Waltham-Watertown directory for 1877-78, 1880, 1882, 1884; and William B. Fowle, “Cash book” (see [footnote 14]).
U. S. patents 161513, applied for November 13, 1873, issued March 30, 1875; 165830, applied for July 14, 1875, issued July 20, 1875; 165831, applied for June 9, 1875, issued July 20, 1875; 179019, applied for May 25, 1876, issued June 20, 1876; and 186838, applied for January 12, 1876, issued January 30, 1877. A French patent was issued to Hopkins on September 12, 1876, and a Belgian patent on September 30, 1876. For lack of records neither has been positively identified but presumably they are for the same device covered in U. S. patent 179019.