Report on the Trials of Implements at Wolverhampton. 4 83 
works, ami fiictorics, and have also arran,E;ed for marine engines. The boiler is 
placed npou a iilate-iron framing which carries the two steam-cylinders, the 
crank-shaft, driving-gear, and rope-drums, and is mounted upon tln-ee road- 
wheels ; it consists of thirty-two wrought-iron tubes arranged in a nearly hori- 
zontal position, that is, with an inclina- 
Fig. 2. — Ideal Vertical Cross-Sec- 
tion of tie Boiler in Messrs. J. 
and F. Hoicard's Patent Self- 
propelling Engine, No. 1168. 
tion of one in eight, and communicating 
at their upper ends with vertical tubes. 
The horizontal tubes are 5 feet in 
length, those of the inner part being 
9 inches in diameter, and the outer 
ones 7 inches in diameter ; and while 
the six tubes of each inner section have 
spaces between them for the passage of 
flame and heated gases from the fire, 
the seven tubes of each outside section 
are placed close to each other, so as to 
fonn, with a covering of lagging cement, 
air-tight walls which are almost non- 
conductors of heat. An idea of the 
arrangement is given in the accompany- 
ing sketch (Fig. 2), a supposed cross 
section of what may be called the back 
of the boiler. Each tube, closed at one 
end, is connected by its other end with 
an upright tube of horse-shoe section ; 
the five upright tubes (shown by the 
dotted lines in the drawing) supporting 
five sets of horizontal tubes, while these 
several sets communicate with each 
other by means of a square tube, A B, 
uniting the ends of the lowest horizontal 
tubes, and by steam connection pipes, 
C C C, at the top of the vertical tubes, 
the blow-off cock. Circulation of water is promoted by an inner tube having a 
The feed-water enters at A, and at B is 
Fig. 3. — Gi-ound-Plan of Messrs. J. and F. Howard's Patent Self- 
propelling Engine, No. 1168. 
slot or opening on its upper side, whicb is inserted in each water-tube ; and the 
slightly tilted position of all the tubes permits the steam to pass freely into 
