Trials of Traction- EiUjines at Wolverliampton. 
5GL 
carried from the cylinder when situated at the fire-box end tow aids 
the chimney via tlie interior of the barrel of the boiler, thus 
putting into the very atmosphere of lUO lbs. steam which is to 
work the engine a 2-inch or 2^-inch pipe, containing steam at 
2 lbs. above the atmosphere, and a few degrees only above boil- 
ing water. 
Brakes. — We have one other general remark to make in rela- 
tion to the engines that were brought to trial. Two of them 
only — viz., Messrs. Aveling and Porter's, No. 7001, and Messrs. 
Tuxford's 10-horse-power, No, 2677, were supplied with brakes. 
We are strongly of opinion that no traction-engine is really 
safe without the ability to apply brake power to the very sup- 
porting wheels of the engine itself. We are of course aware 
that, so long as the connection between the wheels and the 
engine, be it gearing or chains, is in good order and in gear 
with the driving-wheels, the power to control those wheels 
by reversing the engine is the best of all brakes ; but assume the 
driving-wheels not to be in gear, by inadvertence, as happened 
in our experience ; or assume the teeth to strip or the chain to 
break, as happened to another traction-engine at Wolverhampton 
this year (although that engine was not among those we tried), 
then if the engine be without a brake it is wholly uncontrollable, 
and may readily give rise to a fatal accident, as, unhappily, it 
did in the instance of the engine to which we have last referred. 
Trials at Baenhuest. 
After the dynamometer, the next trial to which the traction- 
engines were to be subjected was that of drawing loads upon 
the " course," which for some weeks had been laid down at 
Barnhurst by the engineers of the Society. 
The plan of Barnhurst Farm, Fig. 1, p. 481, and the Section 
on p. 562, Fig. 17, show this course: — The figures on the left- 
hand side of the course indicate the gradients. With the 
the sign -j- before them they indicate ascending gradients (having 
regard to the direction in which the engines were travelling), 
and with the sign — before them they indicate descending gra- 
dients. The figures on the riffht hand of the course indicate 
chains from the starting-point. The whole length of the course 
was a little over \^ mile — actually 144 chains. It will be seen, 
that while the main part of the course was over field surface, a 
portion of it was over farm road, and a portion of it over a turn- 
pike or parish road. On the afternoon of Saturday, the 1st of 
July, the engines were sent up to Barnhurst, for the purpose 
of taking a preliminary run round the course, in order that the 
exhibitors might be accustomed to it, and might know its quali- 
