Fuel consumption

The Dublin Monitor of 3 December 1839 quoted the celebrated Dublin-born adulterer and polymath Dionysius Lardner [who said that Victorians were prudish?] as saying

A train of coaches, about eighty tons, and transporting 230 passengers, with their luggage, has been taken from Liverpool to Birmingham, and from Birmingham to Liverpool, the trip each way taking about four hours, stoppages included. The distance between these places by the railway is ninety-five miles.

This double journey of 190 miles is effected by the mechanical force produced in the combustion of a quarter of a ton of coke, the value of which is 6s.

To carry the same number of passengers daily between the same places by stage coaches, on a common road, would require twenty coaches, and an establishment of 3,800 horses, with which the journey in each direction would be performed in about twelve hours, stoppages included.

Dr Lardner on the Steam Engine

The fuel consumption figure seemed odd to me, because I had recently read about the fuel consumed by a steamer on the Shannon in 1851. This was evidently one of the two screw steamers put to work by the Grand Canal Company in 1851, on which Sir John MacNeill conducted the experiments described here.

A luggage boat propelled by steam, on the screw principle, has been for the first time placed on the waters of the Shannon between Shannon Harbour and Limerick, taking in Portumna, Dromineer, Williamstown [probably Hollands], Killaloe, and the river and canal, to the terminus lock at Limerick.

As a specimen of aquatic architecture, the boat presents no very peculiar or striking features; it is built of iron, with a flush deck; it is capable of carrying about thirty tons, and the rate at which it goes on the canal, is about three and a half miles an hour, whether singly, or as a tug boat with two or three heavy lighters after it; whilst on the broader waters of the river, it is capable of going at a rate of seven and a half miles an hour!

This phenomenon may be explained by the fact that on the canal, which is comparatively narrow, there is no expansion of the waters displaced by the boat, whilst there is always a considerable swell raised about the prow, causes which conspire to retard her speed, and which do not operate when she is on the river.

The expense of working this boat is considerably less than that of the ordinary boat drawn by horses. A ton of coal supplies the engine between Limerick and Shannon Harbour; whereas the horsing alone of a boat between Limerick and Killaloe amounts to something about ten shillings.

The experiment, however, has not been sufficiently tested; and there is some doubt that it may succeed according to the expectations of its projectors. Just now several industrious persons with horses are employed on the canal: and it is to be hoped that in this season of dearth and destitution, no hasty means will be adopted to force them for subsistence on overgrown poor rates.

Limerick Reporter 27 May 1851

The Limerick Reporter article does not say, and I cannot determine, whether this was  Towing steamer No 2 [Appendix 3 in Ruth Delany The Grand Canal of Ireland David and Charles, Newton Abbot 1973], the twin-screw vessel which MacNeill, confusingly, called the No 1 Boat, or the single-screw Towing steamer No 1, which MacNeill called the No 2 Boat.

But I was surprised that the railway train could do 190 miles on a quarter ton of coke while the steamer required a ton for the (roughly) 54 miles from Shannon Harbour to Limerick.

On consulting the online Gutenberg version of the seventh edition of Dionysius Lardner The Steam Engine explained and illustrated; with an account of its invention and progressive improvement, and its application to navigation and railways; including also A Memoir of Watt Taylor and Walton, London 1840, I found that there were some differences between that and the Dublin Monitor‘s version:

A train of coaches weighing about eighty tons, and transporting two hundred and forty passengers with their luggage, has been taken from Liverpool to Birmingham, and back from Birmingham to Liverpool, the trip each way taking about four hours and a quarter, stoppages included. The distance between these places by the railway is ninety-five miles.

This double journey of one hundred and ninety miles is effected by the mechanical force produced in the combustion of four tons of coke, the value of which is about five pounds.

To carry the same number of passengers daily between the same places by stage-coaches on a common road, would require twenty coaches and an establishment of three thousand eight hundred horses, with which the journey in each direction would be performed in about twelve hours, stoppages included.

So 240 passengers, not 230; 4¼ rather than 4 hours — and most significantly 4 tons of coke, costing about £5, rather than ¼ ton costing 6s [£0.3].

Did the Dublin Monitor get it wrong — and, if so, why and how? Or were the lower figures in some earlier edition of Lardner’s work?

 

 

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