steam in the production of draft, would be to sacrifice the greatest excellence attained in the construction of steam-engines since the discovery of separate condensation; beside which this important improvement may very justly be placed. The difficulty has, however, been overcome without the sacrifice of so great an advantage. Instead of allowing the puffs of steam ejected from the cylinders to pass directly to the flue, Mr. Gurney conducts them to a chamber or receptacle, which serves a purpose analogous to that of the chamber between the upper boards of a forge bellows, converting the intermitting puffs into a steady and continuous blast. The steam compressed in the chamber just mentioned, escapes in a number of small jets presented upwards in the chimney; creating a constant and effective draught through the fire, unaccompanied by any noise.
Such are the more obvious qualities of Mr. Gurney's steam-engine, of which it would not be consistent with the limits of this article to give a more detailed analysis, but which the reader will find more fully described in several published works.
I am aware of but three other locomotive engines which are in a sufficiently forward state to give early promise of being practically exhibited on the road. These are the inventions of Dr. Church of Birmingham, Mr. Hancock of Stratford, Essex, and Mr. James Fraser, Hackney Road, London.
In the engine of Dr. Church, a circular fire-grate is surrounded by a number of upright tubes about three or four feet in height, and bent at the top, so as to return downwards in a siphon form. These tubes are made to serve the purpose of flues, in the same manner as those which traverse the Manchester engines. They are contained within other tubes of
