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James Thomson (1803-1870) founder of J. and G. Thomson
1803 December 19th. Born at Broomhill, Partick, the son of John Thomson
1834 August 26th Married Grace McIntyre
Worked for the famous engineer Robert Napier.
1845 Went into business with his brother George Thomson establishing an engineering works in Finnieston Street.
1847 They established a foundry in Anderston, Glasgow.
1851 Living at 13 Kelvingrove Place (age 49 and born at Partick, Renfrewshire), an Engineer employing 200 Men. With wife Grace (age 40) and children Agnes Thomson (age 15), Jane Thomson (age 14), Grace Thomson (age 12), John Thomson (age 11), James Thomson (age 7), Mary Thomson (age 5), Jessie Thomson (age 2) plus two servants. 
The Thomson brothers established a ship yard J. and G. Thomson, named after their foundry.
1861 Living at 13 Royal Crescent, Anderston, James Thomson 57, Engineer and Iron Ship builder, Employing 86 Men And 64 Apprentices, with G Thomson 50, G M Thomson 22, John Thomson 21, engineer, James Thomson 17, draughtsman, Mary Thomson 15, Jessie Thomson 12
1863 James Thomson retired; George took over the business.
1870 March 14th. James died
1870 March. 15th. Obituary. Aged 68 and had been ill for a year. Leaves a widow and family. His sons John and James are in the business in Finnieston Street. Previously to forming his company of J. and G. Thomson he was a senior member with Napier 
See Thomson Family
* 1870 Obituary
The death of another Clyde Shipbuilder and Engineer.
The death is announced of Mr. James Thomson, of the eminent shipbuilding firm of Messrs. James and George Thomson. Mr. Thomson had been ailing for more than a year, and though his death was not altogether unlooked for, it will be accepted with unfeigned sorrow by a wide circle of friends. Previous to the formation of the firm, Mr. Thomson and his brother were long managers of departments in the large shipbuilding establishment of the Messrs. Napier. The deceased was for twenty years the senior member in his firm, and continued to take an active management in the business till about six years ago, when he retired. As is well known, the Messrs. Thomson have sent from their shipbuilding yard , which was one of the most celebrated on the Clyde, some of the fastest and finest boats in the world. The late Mr. Thomson was an excellent specimen of an honest Scotch man, and a shrewd man of business. He was noted for down-right integrity, straightforwardness, and frankness of manner in all his dealings; and was highly respected, not only by the large body of men whom he employed, but by all with whom he came in contact, either in a social or business capacity. He was sixty-eight years of age, and has left a widow and grown-up family to mourn his loss - two of his sons, John and James, constituting the engineering firm of the Messrs Thomson in Finnieston-street.