It is interesting to note the various occupations held by Thomas Thomson, husband of Sarah Wallis Smith Morrin.  At the time of the 1891 census Thomas was a coal miner having previously been a baker, flour miller, and carter.  

I want to first touch on Thomas' occupation as a baker.  I am not 100% sure but it is a possibility that the Thomas Thompson I found in the 1871 census living at the Glasgow Reformatory Institution as a Youthful Offender (Occupation:  Baker) is the one I am seeking. It's interesting to note that Sarah's brother, Peter (Steve's direct ancestor) was also living at the Glasgow Reformatory Institution in the 1871 census, listed as a Scholar (Youthful Offender).  It's possible that Peter and Thomas met there and this lead to Sarah meeting Thomas and marrying him by 1873.  

When Thomas Thomson married Sarah in 1873 he listed his occupation as a Flour Miller. The occupation of Baker in 1871 and Flour Miller in 1873 do not too different.

Interestingly, by 1881, Thomas is a carter (one who carries or conveys goods in a cart), but by the 1891 and 1901 censuses he is a coal miner and they are living in West Calder (1891) and Livingstone (West Lothian), coal mining areas near Edinburgh.

In the 1891 census, they lived at Woodmuir Row, West Calder.  

A description of Woodmuir houses from http://www.scottishmining.co.uk/128.html helps one have a sense of the conditions under which Sarah, Thomas and their children lived.  At the time of the 1891 census, 7 children; eventually they had 9 children.

"There are a few houses (30-40 one-or two-roomed houses) situated in High Blinky which may be considered an (sic) unsatisfactory.  They were built many years ago by a former colliery owner.  They are much after the type of houses (one or two rooms) of those described above.  Again, there is the damp and rough walls, the absence of damp-proof courses, and the moisture exuding from the inner surface; and inthe winter the frost can be rubbed off the internal surface of the walls.  The open ash-pit stands in the centre, with all that previous description carries.  There is the open sewer a few feet from the door.  Washhouses were never thought of, and the living-room served for bath, washhouse, cooking, sleeping, coal-cellar, etc., etc.  The gardens are attached and as the place is situated in a bleak moorland district, you will be able to appreciate the outlook on life the tenants of these houses enjoy."

The family was still living at Woodmuir upon the birth of their last child, Sarah Wallace Smith Morran Thomson.  (Note the spelling of this daughter's middle names as Wallace rather than Wallis and Morran rather than Morrin.)

http://www.scottishmining.co.uk/130.html

Housing in Shale Mining Areas

Livingstone Station

In this village there are 179 houses with a population of 1105 persons. More than 160 of the houses are owned by the Pumpherston Oil Company. The village will compare favourably with most mining villages for general arrangement and position. Most of the houses have little gardens, in front, others have gardens both front and back, as also drying greens fenced off with iron railings. Swings and play centres are provided for the children.

There are seventy-six houses, consisting of room, kitchen, scullery with boiler and sink, also coal-cellar. In forty houses there is a water-closet for every two tenants, and in thirty-six houses a water-closet is provided for each tenant - rental 4s. weekly, inclusive of rates.

Then there are eighty-eight houses having the same accommodation as above, with an attic in addition, which are let at a rental of 4s. 6d. weekly. All the houses have front and back doors. Drying greens are provided. The ground space between the back doors of each house is cemented. All refuse is removed from the dustbins daily by the Company. Two families frequently live in one house, owing to scarcity of houses.

An Institute with library, and a bowling green, are made good use of by the workers. Spray baths are to be had at the Institute, for a small charge. We believe the troubles which arise from time to time are, in a measure, associated with the defective system of sewage disposal, which is discharged in a wood near the village. It should be easily remedied.