The defence of Aden, Yemen according to the magazine Mitteilungen aus dem Gebiete des Seewesens dated 1889 no. 1-2

An item reported that the last two years England and her colonies make all efforts to improve the defence of the British coal stations and arsenals outside Europe. At that moment was for e defence one casemated battery of heavy calibre and several batteries of 15cm breech loading guns available to which 6 and 3pd Hotchkiss quick firing guns were added.