Interesting find.
Jacob Coulthard was living a few doors down from Martha and her Father George Cowie in 1891.
He was aged 7 so did Martha age 20 used to babysit him

George Cowie and Jacob's father both worked at Consett Steel Works.
1891 Census
Residence Place:
Consett, Conside and Knitsley, Durham, England
Registration district:
Lanchester
Sub registration district:
Consett
ED, Institution or Vessel:
7
Piece:4090
Folio:42
So yet more proof to connect Martha and Jacob