Note 39 — Chapter V

It must, however, be mentioned that Mr. Zerah Colburn, in his excellent work on "Locomotive Engineering and the Mechanism of Railways," points out that Mr. Davies Gilbert noted the effect of the discharge of the waste steam up the chimney of Trevithick's engine in increasing the draught, and wrote a letter to "Nicholson's Journal" (Sept., 1805) on the subject; and Mr. Nicholson himself proceeded to investigate the subject, and in 1806 he took out a patent for "steam-blasting apparatus," applicable to fixed engines, which, however, does not seem to have come into use. (See ante, p. 82.)