4'i8 Report on the Trials of Implements at Oxford. 
withont boilers the case is very different. Here each engine is worked off a 
boiler belonging to the Society. With equal diligence and ability, and similar 
quantities of coal, it is clear that equal quantities of water should be evaporated 
during the trial of each engine ; and if this is not the case it is a fair assump- 
tion that the difference lies in the want of skill in the stoker. It is to be 
regretted that the Society did not deem it necessary to provide for the Oxford 
Show a very simple apparatus, which would have enabled us to readily 
ascertain the facts ; as it was, one had to be improvised and carefully watched, 
which proved a difScult matter, as it is hard to persuade a man working a 
pump that there can be any harm in pumping water out of a vessel at any 
moment he wants to pump it. He does not understand the object, thinks it 
all nonsense, and is very apt to disregard orders. As the apparatus was not 
got ready for the first of these trials, and as we do not possess reliable records 
of all the evaporative results, we do not tabulate those we have ; but call 
attention to two experiments, which show in a striking manner the difference 
due to skill in firing. A comparison was made between the stoking of the 
Eeading Iron Works, No. 4010, and of Messrs. Marshall, Sons, and Co., 
No. 7082. The Reading Company's man evaporated as much as 9'37 lbs. of 
water for each 1 lb. of coal burnt. Messrs. Marshall's man evaporated only 
8 lbs. of water for each 1 lb. of coal burnt. The boiler being the same, the 
difference represented solely the skill of the fireman. Now the Reading Com- 
pany's engine ran for 3 hours 18 minutes and 54 seconds of " break time," and 
burned 4"22 lbs. of coal per horse-jTOwer per hour, while Messrs. Marshall's 
engine ran only for 2 hours 42 minutes G seconds, and burned 5'18 lbs. of 
coal per horse-power per hour. But while the Reading Company obtained 
937 lbs. of water turned into steam for 100 lbs. of coal burnt, Messrs. 
Marshall obtained only 800 lbs., and therefore their engine never had the same 
chance of doing work as that of the Reading Company, for it never had the 
same steam wherewith to do it. If the fireman of the Reading Iron Company 
had also fired for Messrs. Marshall and Sons, and with equal ability, they 
would have had their 937 lbs. of water evaporated for the 100 lbs. of 
coals, and their engine, instead of having run only 2 hours 42 minutes 
6 seconds, would have run 3 hours 9 minutes 51 seconds, and their con- 
sumption, instead of being 5"18 lbs., would have only been 4'22 lbs. of coal 
per horse-power, per hour. 
When considering the consumption of fuel per horse per hour of the engines 
in Class 2, worked off the Society's boiler, it should be borne in mind that 
in almost all non-condensing engines of the present day the waste steam is 
made to heat the feed water, and most properly so, because the difference or 
saving between using feed water at GO degrees, and at, say, 200 degrees, is about 
13|- per cent, of the coal required to turn it into steam ; or a given weight 
of coal being used in both cases, about 15 per cent, more effect would be ob- 
tained from well heated feed water than from cold. Formerly it was commonly 
thought that if water were heated nearly boiling hot it would save nearly the 
whole coal, but now everybody knows that the principal absorption of heat in 
turning water into steam is not providing the sensible heat which goes to make 
water feel hot, but in imparting the latent heat required to convert the liquid 
into a vaporous condition. Unhappily, this Society has never provided any 
means for heating the water for its boiler from the waste steam of the engines 
under trial, and thus the whole of the fixed engines tried with the Society's 
boiler exhibit a consumption 13^ per cent, higher than they would^do were this 
simple provision made.* One very small advantage, however, that the engines 
had during the trial was, that they were not required to pump the feed water 
into the boiler, that operation being done by hand. 
• This was a point referred to by the Bury report. 
