Janet Shedden and James Adam

James Adam and Janet Shedden lived in the Parish of Beith, Ayrshire, The Isle of Lewis and Edinburgh. Three of their children emigrated to New Zealand (James, Elizabeth and John).

This family is of interest because ancestry.co.uk has found a DNA match between a descendant of Janet and James Adam's Son, John Shedden Adam, and a descendant of Alexander Hall Shedden from Trivandrum in South East India.

The most credible source of information I have found regarding John Shedden and Barbara Wilson comes from the Memoir of William Wilson of Crummock. Some of the dates in the memoir can be confirmed from the Old Parish records of Scotland available at scotlandspeople.gov.uk
I copy below extracts from that memoir:

Janet (Shedden), born 28th March 1788; married, 10th August 1807, James Adam, W.S., and factor on the Drummond estates in Perthshire. Mr Adam gave up the factorship, and, on his own account, entered into extensive speculations and improvements in land in his native parish of Lochwinnoch, which financially proved disastrous. He afterwards for a time became factor in Lewis for Mackenzie of Seaforth, but ultimately resided and practised as W.S. in Edinburgh.

A man of considerable originality, he invented the screw propeller, and, along with his son James, experimented successfully on a fishing boat at Leith. In 1832, the result was laid before the Admiralty as being an invention eminently adapted for moving ships of war, but it was not approved of. Unfortunately Mr Adam took out no patent for his invention, which was afterwards applied for by, and granted to, Francis Potter Smith, of Hendon, in 1836. The correspondence between Mr Adam and the Board of Admiralty was printed in pamphlet form by Ballantyne & Hughes, Edinburgh, circa 1837.

Mr and Mrs Adam had surviving issue:

Matilda, born 30th August 1812; died unmarried.
James, civil engineer, married Margaret, daughter of ... French of Edinburgh; emigrated to New Zealand in 1840, and was drowned through the capsizing of the ship's boat during a squall in Manukau Bay on 23rd November 1841, leaving, besides his widow, one child, both of whom afterwards died in Sydney, N.S.W.
Barbara, who died unmarried.
Janet,who died unmarried. (Janet and Barbara were twins)
Margaret, now residing in Edinburgh.
Elizabeth, who accompanied her younger brother to New Zealand, married Rowan Ronald of Sydney; issue, a daughter, but both the mother and child died there soon after.
John Shedden, emigrated to New Zealand, and from thence went to Sydney, where he was for many years head draughtsman in the Government Survey Department. He married Luisa-Ann, eldest daughter of James Dalgarno of Sydney, and has issue:

Luisa Janet Elizabeth, who married, on 2nd November 1881, the very Revd. T. R. Curwen Campbell, Archdeacon of Bathurst, N.S.W.; issue: - a son, Robert Curwen, born 12th November 1895.
Janet Blanche.
Margaret Elsè, who married, on 19th February 1891, Charles Ernest Young of Fairymead, sugar planter, Bundaberg, Queensland, and has issue, a son, Henry Shedden Baring, born 15th April 1894.
John Shedden, now architect in Sydney.

Mary, who died young.

Mr Adam died in Edinburgh on 3rd December 1849, and Mrs Adam in 1863