Ryan, Patrick (5. juli 1973): «The last word on... The early and the late»[død lenke]. New Scientist. Sitat: «For oss, øyeblikket 8,17 om formiddagen betyr noe – noe meget viktig, om det skjer på starttid for vårt daglige tog. For våre forfedre var et slikt merkelig eksentrisk øyeblikk uten betydning – det eksisterte ikke en gang. Ved å oppfinne lokomotivet ble Watt og Stephenson delvis oppfinnere av tiden.»
Torrens, H. S. (2006): The geological work of Gregory Watt, his travels with William Maclure in Italy (1801–1802), and Watt's «proto-geological» map of Italy (1804)411. s. 179–197. doi:10.1130/2006.2411(11).
McCabe, Joseph (1945): A Biographical Dictionary of Ancient, Medieval, and Modern Freethinkers, Haldeman-Julius Publications. Sitat: «He made such improvement in the crude steam-engine that had been invented before his time that he is usually described as the inventor. «His many and most valuable inventions must always place him among the leading benefactors of mankind,» says the account of him in the Dictionary of National Biography. He was an accomplished man. He knew Greek, Latin, French, German and Italian and was very friendly with the great freethinking French scientists. Andrew Carnegie has written a life of him and describes him as a deist who never went to church.»
«James Watt's legendary 'magical retreat' to be revealed at Science Museum». (Pressemelding). Science Museum (London). 1. mars 2011. Arkivert fra originalenArkivert 5. januar 2014 hos Wayback Machine. den 25. mars 2011.
«James Watt's legendary 'magical retreat' to be revealed at Science Museum». (Pressemelding). Science Museum (London). 1. mars 2011. Arkivert fra originalenArkivert 5. januar 2014 hos Wayback Machine. den 25. mars 2011.