Nice to hear from you! Robert was the 4th of 8 children: MARGARET b.abt. 1831, I have no info on her, she was a 9yo in the 1841 census but wasn't with the family in the 1851. MARY b.abt. 1833, married Robert Lang 1st Dec 1854, Maybole, and died 22nd Apr 1915, Glasgow. WILLIAM, b. abt. 1837 & died bef. 1851. ROBERT (my g,grandfather) was born 1841 & died 1921. JAMES b. abt 1845 married Annie McLaren 14th Apr 1868. He died 17th Sep 1926. ELIZABETH b. 1847 I had no other info on her and lost her after the 1861 census. JOHN b. 1850, married Mary Shaw, 31st Dec 1876. He died 18th Jul 1920, And finally, the 2nd WILLIAM b. 28th Feb 1852, he married Helen McLure. They emigrated to the U.S. in 1888 They lived in Philadelphia, Pennsylvania where he died 29th Mar 1907.
I hope that helps you, and any further info on Elizabeth (places, dates events) would be gratefully received.