688 
Report on the Trials of Portable 
6 feet long and 6 inches diameter, closed at each end by a cast-iron chamber 
having radial divisions. Six copper pipes, If inch diameter, run from end to 
end of the heater, their extremities being jointed to the radial divisions of the 
terminal chambers in such a way as to constitute them, together, a continuous 
coil ; while each copper tube has a spiral twist given it to allow of expansion. 
Tiie exhaust-pipe passes right through the heater, which it enters through 
a stuffing box, to allow of expansion. Openings in the exhaust-pipe give exit 
into the heater of a jiortion of the exhaust steam sufficient to heat the feed- 
water. 
The exhibitors elected to run at 130 revolutions, and 
135 lbs. pressure, with a brake -load of 17 - horse - power. 
Mr. Henry McLaren fired the engine, and exhibited a com- 
bination of sangfroid and skill, which challenged admiration 
again and again, as certain " troubles " developed themselves 
in the course of the run. The engine had scarcely started when 
a screaming noise, referred to the governor, declared itself. A 
little worried, no doubt, by the circumstance, but outwardly 
unmoved, Mr. McLaren did not discover, until the run had 
lasted for nearly an hour and a half, that his regulator handle 
was not fully open. Scarcely had he rectified this, when the 
"scream" became a loud "knock" and the engine slowed. 
Stopping at 12*10, it was found that the Hartnell-Turner 
governor had moved round on the shaft, the effect being to shift 
the expansion eccentric and upset the setting of the slide. 
This resulted from a piece of pure carelessness in the shop 
With a view to occasional reversing, the governor was furnished 
with a slot which had been cut the wrong way. As a con- 
sequence, the bolt, whose proper office was merely to secure the 
governor, either in the forward or back position, became a 
driver, getting loose after a time with the results already men- 
tioned. Eight minutes were spent in putting matters right, and 
added accordingly to the length of the run, the engine starting 
again at 12 "18. From the moment of restarting, she became 
quiet and regular in action, although it was evident that the 
control of the Hartnell-Turner governor was not perfect. But 
Mr. McLaren, in spite of many demands on his attention, kept 
his steam pressure so even that, the load being constant, this 
was very little noticeable. 
Mishaps notwithstanding, this engine made a run of 4 hrs. 
23 min. actual, and 4 hrs. 34| min. mechanical time, with a 
coal supply of 199j lbs., equal to a consumption of 2*68 lbs. 
per horse-power per hour. 
C'linpound Portable Engine bg Messrs. J. and H. McLaren 
(No. 3107). — This came to the brake on Monday morning the 
11th, or at a moment when Davey Paxman's and Foden's Com- 
pounds had nearly tied in respect of consumption, wliile the 
former maker had, as nearly as possible, tied with McLaren in 
