Hello,
NJ makers mark is for Numa Jacques, 16 Warstone Parade, Warstone Lane, Birmingham, first registered with Birmingham Assay Office on 11th December 1883 as a watch manufacturer. An excellent book on the subject of Makers Marks on pocket watches is Phillip T. Priestley's 'A History and Register of Gold & Silver Watch Case Makers of England 1720-1920' from which this information is taken. I hope this helps, kind regards.