Slow progress in invention of the steam-engine--Thomas Newcomen of Dartmouth--His study of steam-power--Correspondence with Dr. Hooke of the Royal Society--Newcomen’s experiments--Assisted by John Calley--Newcomen’s atmospheric engine--Newcomen and Calley erect their first engine--Humphrey Potter the turn-cock boy’s contrivance--Engines erected at Newcastle-on-Tyne, Leeds, and Cornwall--Wheal Fortune engine--Mr. William Lemon--Joseph Hornblower--Jonathan Hulls and steam propulsion of ships--His steamboat--Extended use of the Newcomen engines in Cornwall and northern mining counties--Payne, Brindley, and Smeaton, improvers of the steam-engine 59–76 CHAPTER V. James Watt, his birthplace and lineage--His grandfather the mathematician--Cartsdyke and Greenock in the last century--James Watt’s father--His multifarious occupations--His mother--Watt’s early years--His fragile constitution--Sent to school--His first visit to Glasgow--His indulgence in storytelling--His boyish ingenuity--His home education--The Stuart rebellion--Watt’s love of scientific pursuits--Sent to Glasgow to learn the trade of mathematical-instrument maker 77–95 CHAPTER VI. Glasgow in 1754--The Glasgow tobacco lords--The early clubs, and social habits of the merchants--Watt’s master--Leaves Glasgow, and proceeds to London on horseback--Is placed with a mathematical-instrument maker--His progress in learning the trade--Frugal living in London--Danger from pressgangs--His infirm health--Returns to Scotland--Refused permission to begin business in Glasgow--Gains asylum in the College--His workshop there--Makes musical instruments--His various reading and studies--Intercourse with the professors--Intimate relations of Watt with Robison--Robison’s estimate of Watt 96–116 CHAPTER VII. Robison and Watt’s conferences on the power of steam--Dr. Black and latent heat--Watt’s experiments on steam--His apparatus--The college model of the Newcomen engine arrives from London--Watt’s experiments upon it--His difficulties and perseverance--His instrument-making business improves--Takes a partner and opens a shop in the Salt Market--His marriage--Continued experiments on steam--His Sunday walk on Glasgow Green, and his first idea of the condensing engine--His experiments with the model, and successive difficulties--Anecdote of Watt and Robison and the new apparatus--The model engine--Removes to a cellar and erects a working engine--Mechanical and financial difficulties 118–137 CHAPTER VIII.