Ltd, Edinburgh were publishers of
Reliable Series of post cards and related products.
Here is a W R & S Ltd album of photographs published in the early
1900s. The photos range in size from about 2ins
x 1.5ins up to 9.5ins x 6.5ins. The copy I have has a blind stamp
on the cover reading:
Andrew Elliott, 17 Princes Street, Edinburgh
Between the words RELIABLE and SERIES in this advert, there is a
shield (hardly visible in the reproduction below. It contains the letters 'W R & S'