Trials of Portable Steam- Engines at Cardiff. 
63 
driven tliroii<;li the intervention of a slot, and it is the weight alone which 
canses the slide-valvo to be shortened, as the mere falling of ttie governor 
ball would, owing to the presence of the slot, have no cUect whatever in 
shortening the slide. 
The steam is taken by an internal steam-iMjie, extending from the cylinder 
up into a stcam-donie placed over the fire-box, in which donae there is the 
steam-regnlator, or starting valve. 
The exhaust steam, from the two ends of the cylinder, goes into a central 
belt cast round the cylinder. On the upper part of the belt a steam-blast 
nozzle is placed, while from the lower part a branch proceeds to convey steam 
into a flat steam-heater, bent round about the inside of the smoke-box. 
In the steam-heater there are several feet run of f" brass pipe ; this pipe is 
surrounded by the waste steam, and in the pipe circulates the water from the 
rising clack-box of the feed-pump. The heated water passes through a stop- 
back valve-box, into the boiler, through the front tube-plate of the boiler. 
The exhaust steam which is condensed in heating the feed-water, escapes by 
a pipe at the bottom of the smoke-box. 
The feed-pump lies at an angle, is bolted to the barrel of the boiler, and is 
worked off the eccentric provided for it. It is always drawing; the surplus 
water is returned to the feed-vessel ; there is also a cock by which the water 
can be sent direct into the boiler without being heated. 
The back end of the fire-box below the fire door is made without any water- 
space whatever, that is to say, that so far as the water space of the fire-box is 
concerned, the fire door is not merely an oval orifice, but is an opening 
extending from the verj'' bottom of the box up to the arch over the door, 
which is of the usual semi-elliptical figure of a fire-door frame. 
The space below the door is filled in by a cast-iron plate, lined with fire-bricks. 
The Exhibitors attribute to this construction the advantage of getting rid 
of a cause of wear in the fire-boxes, as ordinarily made with a water space 
below the door, as they allege that it is in that part that fire-boxes most speedily 
give way ; they also point out that this iar-e opening is very convenient when 
it is necessary to do repairs inside the fire-box. 
Tha bearing-wheels of the engine have wrought-iron spokes, and wrought-iron 
inner and outer rims ; the spokes are cast into the bosses, as are also the boxes, 
which are chilled. The hind axle is of wrought iron carried in brackets attached 
to the fire-box ; the fore axle is also of wrought iron, attached to the under side 
of a wood bed. This bed carries the wheel-plate, which bears against a 
wrought piece, fastened under the front part of the barrel of the boiler some 
little distance back from the smoke-box ; in fact the fore axle is so placed 
that the front wheels just clear the hind ones in locking. 
The barrel and fire-box are cleaded all over. The ash-pan and damj)er arc 
of the usual construction. 
This engine was tried twice ; the double trial arose in the following 
manner : — 
On the occasion of the first trial the engine ran for 4 h. 47 m. actual time, 
and for 4 h. 51 m. 18 s. mechanical time, representing a consumption of 
2"884 lbs. of coal per brake horse-power per hour. 
The quantity of water evaporated from 212° was 2319 lbs. 
The engine was perfectly steady in its running, and the governor had it 
completely under control in the trial made in respect of that head of merit in 
an engine. 
This being the state of the case, the engine of the Reading Iron Works 
Company (Limited) (No. 2927) was tried ; the full particulars of this trial 
will be given when describing that engine, it will suffice here to state, that it 
ran for 4 h. 51 m. 36 s. mechanical time, giving a consumption of coal of 
2*881 lbs. per brake horse-power per hour. 
