56 
Report of the Judges on the 
" 5tli. The Commercial, or as it is now frequently called, the 
Nominal horse-power. This is the horse-power, about which no 
two persons can agree." 
Such are the obstacles that beset men acquainted with the 
subject, when they endeavour to settle the question, while, as 
before mentioned, those who have not that acquaintance, see not 
the slightest difficulty in dealing with the matter. 
As an example of this, an enthusiastic bystander rushed up 
to one of the stewards at Cardiff, to point out the gross unfair- 
ness of the trials, because an exhibitor was working an 8-horse 
engine at a greater power than 8-horse on the brake. This 
gentleman was not a manufacturing engineer, and we need 
hardly say he was not a purchaser of steam-engines. The pur- 
chaser, no doubt, would wish to be delivered from such a solver 
of the Commercial horse-power difficulty. 
The Judges are sorry to have consumed so much time in 
considering this question of Commercial horse-power, but they 
have done so, in order that their readers may be in possession 
of the history of the Society's efforts on the subject; and that 
they may see how great are the difficulties in the way of a solu- 
tion of that which, at first sight, appears so simple a question. 
No restriction as to the horse-power at which the engines 
were to be worked on the dynamometrlcal brake were imposed ; 
the Exhibitor was left at perfect liberty, so long as he did not 
exceed the declared pressure of steam. Condition VI., which 
regulated these questions, was as follows : — 
" Exhibitors shall, on making their final specifications, elect at what steam- 
pressure not exceedin<T the declared pressure, what horse-power on the brake, 
and what number of revolutions they would wish to be tried." 
Conditions as to the engines being each worked by one man, 
as to taking the indicator diagrams, as to ascertaining the evapo- 
ration of water, and as to the amount of oil and tallow used, 
were laid down similar to those which were stipulated for at 
Wolverhampton. 
On this occasion, at Cardiff, the whole of the Exhibitors who 
entered " engines," entered them as 8-horse power ; one maker, 
however, did not venture, in the Catalogue, to state the horse- 
power, but gave simply the diameter of his cylinder. All the 
engines were single-cylinder engines ; the two-cylinder type, of 
Avhich, as before stated, several were exhibited in 1867 at Bury, 
being now entirely abandoned in engines of the 8-horse size. 
Two additional, and most salutary conditions were imposed on 
the Exhibitors ; they are given in the latter part of Condition V.^ 
and are as follows : — 
" Over and under-running will not be permitted; steady running as nearljv 
