Hi Wee Mammy
Have you checked the 1851 and 1861 England censuses for Matilda?
In the 1851 England census, there is a Matilda Robertson, age 29, born Glasgow, Scotland, employed as a daily governess in the household of Maria Evans at 8 Southampton Row, Marylebone.
In 1861, this same Matilda Robertson, age 40, is in the employ of the Lady Superintendent of the Governess House at 66 Harley Street, Marylebone.
As your Matilda is not recorded in the Scotland censuses for those years, these look like a good fit. While they may not have married, Matilda appears to have taken his surname.
Matilda Robertson next appears in the 1871 Scotland census you cited, age 50, with Archibald Robertson at 57 Kirk Street, Calton.
In 1861, Archibald Robertson, age 51, Cotton Spinner, is living at 9 St Andrew Lane, Calton, with his son John, age 20; Janet Robertson, age 6, daughter; Mary McMillan, age 80, his mother, who is recorded merely as 'relative'; and Ann McMillan, age 40, presumably his sister, who is likewise merely recorded as 'relative'.
Do you know who is the mother of Archibald's daughter Janet (born in Glasgow circa 1855)? In 1871, Janet Robertson, age 16, is living with her brother, John Robertson, age 30, tobacco spinner, his wife, Elizabeth, and their children Archibald, age 7, Alexander, age 6, and Elizabeth, age 1, at 52 Rose St, B Land (sic), Hutchesontown, Govan.
What became of Jane Black remains a mystery, as she isn't with Matilda in England -- nor can I find any trace of Archibald Robertson in the either the 1851 Scotland census or 1851 England census. He seems to have slipped under the radar.
Cheers,
Rodeo
