Trials of Portable Steam- Emjines at Cardiff'. 65 
developing 8-horsc power (and therefore the consumption should have been 
small in proportion to what it would be when the engine was doing full 
work), the heat in the smoke-box was very considerably in excess of that of 
other nominal 8-horse power engines, which were being worked at as much 
as 14-horse power. 
The bearing-wheels are wood, running on wrought axles. 
The governor could not control the engine at all ; serious use of the hand- 
regulator was required. 
The actual time running was 1 h. 28 m. 25 s. The mechanical time was 
1 h. 23 m. 36 s., giving a consumption of just 10 lbs. of coal per brake horse- 
ix)wer per hour. 
The gross indicated horse-power was 9"1, and the consumption of coal for 
each such horse-power was 8'30 lbs. per hour. 
The temperature of the feed- water was about 120°. 
Fig. 2. — Indicator-Diagram of Mr. E. Hayes' Poriahle Engine, No. 
4834 (No. 3 diagram, 48 lbs. spring.) 
The engine was so indifferently managed, that it was impossible to keep the 
water at the proper height in the gauge, and when the trial was ended it had 
disappeared from the glass. The water was probably at such a distance below 
the starting level as would have required about 16 gallons to fill up; this, 
added to the quantity noted (30 gallons) would give 46 gallons as the total 
evaporated, and of this the 30 gallons would be from cold water. The evapo- 
ration of these 30 gallons is treated as from cold water, because, in this 
instance, the steam which heated the feed-water became mingled with it, and 
had to be re-evaporated, and thus the effect was practically the same (so far 
as the boiler duty only was concerned) as evaporating from cold water. This 
\Mm.t was noticed in last year's Report. 
Such an evaporation is equal to about 50'9 gallons from 212°, equal to 
4-54 lbs. of water per lb. of coal. 
It would appear that the boiler did about one-half, or rather less than one- 
half, its duty in making steam, and that the engine did about one-half its duty 
in \;sing it; thus a final result of nearly four times the least consumption of 
coal per horse-power per hour was reached. 
The next engine in order of trial was (No. 4959) Davey, 
Paxman, and Co., of Colchester. Price 230/. 
This engine has a cylinder 8f-inch diameter, 1 foot length of stroke, a 
total heating-surface of 168*4 square feet, fire-grate of the full area of 3'75 
square feet undiminished by fire-brick while running. 
The exhibitors elected to run at 80 lbs. pressure, at 115 revolutions per 
minute, and at 12-horse-power on the brake. 
VOL. IX.— S.S. F 
