He was encouraged to persevere in the completion of his safety-lamp by the occurrence of several fatal accidents about this time in the Killingworth Pit. On the 9th of November a boy was killed by a blast in the _A_ pit, at the very place where Stephenson had made the experiments with his first lamp; and, when told of the accident, he observed that if the boy had been provided with his lamp, his life would have been saved. On the 20th of November he went over to Newcastle to order his third lamp from Mr. Watson, a plumber in that town. Mr. Watson referred him to his clerk, Henry Smith, whom Stephenson invited to join him at a neighboring public house, where they might quietly talk over the matter, and finally settle the plan of the new lamp. They adjourned to the "Newcastle Arms," near the present High-Level Bridge, where they had some ale, and a design of the lamp was drawn in pencil upon a half-sheet of foolscap, with a rough specification subjoined. The sketch, when shown to us by Robert Stephenson some years since, still bore the marks of the ale. It was a very rude design, but sufficient to work from. It was immediately placed in the hands of the workmen, finished in the course of a few days, and experimentally tested in the Killingworth Pit like the previous lamps on the 30th of November, by which date neither Stephenson nor Wood had heard of Sir Humphry Davy's experiments, nor of the lamp which that gentleman proposed to construct. [Illustration: DAVY'S SAFETY-LAMP.] [Illustration: STEPHENSON'S SAFETY-LAMP.] An angry controversy afterward took place as to the respective merits of George Stephenson and Sir Humphry Davy in respect of the invention of the Safety-lamp. A committee was formed on both sides, and the facts were stated in various ways. It is perfectly clear, however, that Stephenson had ascertained _the fact_ that flame will not pass through tubes of a certain diameter--the principle on which the safety-lamp is constructed--before Sir Humphry Davy had formed any definite idea on the subject, or invented the model lamp afterward exhibited by him before the Royal Society. Stephenson had actually constructed a lamp on such a principle, and proved its safety, before Sir Humphry had communicated his views on the subject to any person; and by the time that the first public intimation had been given of his discovery, Stephenson's second lamp had been constructed and tested in like manner in the Killingworth Pit. The _first_ was tried on the 21st of October, 1815; the _second_ was tried on the 4th of November; but it was not until the 9th of November that Sir Humphry Davy presented his first lamp to the public. And by the 30th of the same month, as we have seen, Stephenson had constructed and tested his _third_ safety-lamp.