This is an original paper flier advert or leaflet dating back to the 1890s and the early days of electric lighting.   Produced by Woodhouse & Rawson United Ltd of London it mentions the explorer Stanley in an engraved picture by Albert Snell of white explorers bringing light to 'darkest Africa'.    On the reverse it lists the various buildings, Government Offices, companies and presumably wealthy individuals etc. who have used their services.   The Victoria & Albert Museum have an almost similar copy of this, and if you Google  'collections.vam.ac.uk/item/O827584  [note, that's a capitol 'O', not a zero] you'll see their full  description, except that theirs is apparently on card and it doesn't mention any writing on the back, unlike this one.  Quite a fascinating bit of history on many levels.

It measures 22cm  x 14 cm.   Condition is pretty good considering its age...it has been folded in the past and has a couple of slight tears along the creases above the picture.   Paper is off-white now and there is very slight, light foxing.    Can't be many of these about now...if any...   Price included postage.