Marjery
When the horse was king, horseman was a common occupation particularly on farms.
For some it was part of an apprenticeship, others a career.
My wifes father was another Robert Corlett and a horseman on his fathers farm in his younger days
He was born a few miles away and we still have a picture of him working his team of three
They were mechanically reaping the harvest in the late 1930s on his own Andreas farm.

Sarah J. Mason was at 18 South Quay Douglas, St Mathews parish under Braddan (born Malew)
With just her three children all born in Marown (ref RG13-5305-14-110)
William Mason appeared to move around possibly for work as he is in different places each census.
Peter.