§2. Experiments on the Quantity of Fuel consumed by the Engines.

The above formula, which is of easy application, gives the absolute quantity of fuel required by an engine in all circumstances, provided the consumption of the engine in a given case be known.

The only thing necessary, will therefore be, to make one experiment on the fuel consumed by the engine with a given load, which will be the data of the problem.

Evidently between two different engines, this first data will differ according to the particular construction of each engine, and chiefly according to the extent of heating surface of its boiler. The following experiments were therefore undertaken on the Liverpool and Manchester Railway, in order to obtain a knowledge of this data, and likewise to verify the theoretical principle exposed above.

In these experiments the tender was first carefully emptied, then the coke was accurately weighed and put into the tender. The fire-place of the engine was besides filled with fuel, up to the lower part of the door. At the end of the experiment, the fireplace was again filled to the same height, and the coke remaining in the tender was weighed with the same care as at setting off.

As an engine that ascends alone, with its train, an inclined plane exerts necessarily a greater effort

than if at that moment it were helped by an additional engine, we have put down whether the engine was helped or not in going up the plane. We have also incribed the state of the weather and the temperature of the water in the tender, in order that those circumstances might be taken into consideration.

In these experiments, the co-operation of the persons attached to the establishment was often necessary. We must particularly mention Mr. J. Dixon, the resident engineer, to whom we are indebted also for his accurate levelling of the road, and many other pieces of information obligingly communicated to us.

VULCAN,from Liv. to Manch. 1 July
Do.

LEEDS, from Liv. to Manch. 15 Aug. 20 waggons
Do. from Manch. to Liv. 15 Aug.

20 waggons

from Manch. to Liv. 22 July 9 first class carriages

8 do.

of which 1} at half way

The engine is still a little stiff. It comes out of the repair-yard.

In examining these experiments, we find that neither the pressure in the boiler, nor the velocity of the motion, have any remarkable influence on the result. This fact was already indicated by theory.

We also remark the advantage that is found, in respect to fuel, in making the engines, whenever it is possible, draw the greatest loads their power will permit. For instance, the ATLAS, drawing a load of 25 t., consumed 720 lbs. coke, whereas, in drawing 190 t., or a load eight times as great, it only consumed double the quantity of coke. This difference must evidently, as we have explained above, be attributed to the expense of power necessary in each case, in order to overcome the resistance of the atmosphere, the engine, and its tender.

We must add, that in those experiments the coke employed was of prime quality, or Worsley coke, which is prepared on purpose for iron-founderies. When gas-coke is used, the engines consume about 12 per cent. more, without reckoning the loss resulting from the friability of that combustible. It has moreover been ascertained, that the sulphurous parts it contains are highly destructive of metals. For that reason its use has been completely given up on the Liverpool Railway, notwithstanding its low price.

In making use of coals of good quality, the quantity required is nearly the same as that of good coke; but this combustible has in regard to the