Note 24 — Chapter V · THE FIRST GLIMMER OF THE SAFETY-LAMP.

Watt’s first patent was in the year 1769, and that for his double engine was in 1781. Dr. Davy, in speaking of the Wherry Mine as being a place of favourite resort with his brother during his youth, says, “The steam-engine there (an invention,” he adds, “which had only a short time before been perfected by Mr. Watt) was one of the earliest that had been introduced into Cornwall.”