Talk:The Coal Question

I have two problems with the entry as it now stands. One is that there seems to be an excessive effort to make Jevons into a modern man thinking about modern problems. The other is that I'm not sure that Jevons really said that Watt's steam engine was "merely an efficiency improvement over prior designs". If he did he deserves to be pulled up on it. The important thing about Watt's engine was that it produced rotary motion so that it could be used to drive machinery directly. It's important to remember that British coal was so cheap that there was no great benefit from using it efficiently in the major industrial areas on or near the coalfields. As early as the 1830s British steam engines (which generally followed Watt's preference for LP steam) were criticised for their inefficiency by users in France and Belgium where coal was much more expensive.

When J says somethng which is debatable I prefer to say that he 'argued' it rather than seeing it or pointing it out.

If I get a chance I will have another look at J's book to see if the entry can be made more reliable.

scepticc Scepticc (talk) 12:23, 29 June 2008 (UTC)

Response: Jevons as "Modern Man" and his Engine Analysis

As the author of this entry, I would argue that no effort was made to make Jevons any more of a modern man than he was. Jevons was thinking about modern problems. Or, more accurately, he was thinking about THE modern problem. The standard of living that defines our modern age is made possible because of our use of non-renewable fuels, a situation that is not sustainable.

Regarding the "Jevons Paradox," I've copied below the relevant passages from the book:

It is wholly a confusion of ideas to suppose that the economical use of fuel is equivalent to a diminished consumption. The very contrary is the truth.

As a rule, new modes of economy will lead to an increase of consumption according to a principle recognised in many parallel instances. The economy of labour effected by the introduction of new machinery throws labourers out of employment for the moment. But such is the increased demand for the cheapened products, that eventually the sphere of employment is greatly widened. Often the very labourers whose labour is saved find their more efficient labour more demanded than before. Seamstresses, for instance, have perhaps in no case been injured, but have often gained wages before unthought of, by the use of the sewing-machine, for which we are so much indebted to American inventors.

So it is a familiar rule of finance that the reduction of taxes and tolls leads to increased gross and sometimes even nett revenues; and it is a maxim of trade, that a low rate of profits, with the multiplied business it begets, is more profitable than a small business at a high rate of profit.

Now the same principles apply, with even greater force and distinctness, to the use of such a general agent as coal. It is the very economy of its use which leads to its extensive consumption. It has been so in the past, and it will be so in the future. Nor is it difficult to see how this paradox arises.

The number of tons of coal used in any branch of industry is the product of the number of separate works, and the average number of tons consumed in each. Now, if the quantity of coal used in a blast-furnace, for instance, be diminished in comparison with the yield, the profits of the trade will increase, new capital will be attracted, the price of pig-iron will fall, but the demand for it increase; and eventually the greater number of furnaces will more than make up for the diminished consumption of each. And if such is not always the result within a single branch, it must be remembered that the progress of any branch of manufacture excites a new activity in most other branches, and leads indirectly, if not directly, to increased inroads upon our seams of coal.

It needs but little reflection to see that the whole of our present vast industrial system, and its consequent consumption of coal, has chiefly arisen from successive measures of economy.

Civilization, says Baron Liebig, is the economy of power, and our power is coal. It is the very economy of the use of coal that makes our industry what it is; and the more we render it efficient and economical, the more will our industry thrive, and our works of civilization grow.

The engine is the motive power of this country, and its history is a history of successive steps of economy. Savery recommended his engine for its cheap drawing of water and small charge of coals. But as he allowed the steam to act straight upon the water, without the intervention of a piston, the loss of heat was tremendous. Practically, the cost of working kept it from coming into use; it consumed no coal, because its rate of consumption was too high.2 Newcomen made the first step towards the future use of the engine, by interposing a piston, rod, beam, and pump, between the steam and water. It was asserted that mines formerly drowned out and abandoned might sometimes, when coal was very cheap, be profitably drained by his rude atmospheric engine. But when Brindley went to Wolverhampton, to inspect one of these engines, he formed the opinion "that, unless the consumption of coal could be reduced, the extended use of this steam-engine was not practicable, by reason of its dearness, as compared with the power of horses, wind, or air."3

Smeaton, the most philosophical of engineers, after a careful study of the atmospheric engine, succeeded in nearly doubling its efficiency. The engine had long been hanging on the verge of commercial possibility; he brought it into successful use, and made it both possible and profitable. But in this branch of his art he willingly gave place to that even greater man, who, after long continued scientific and practical labours, made the steam-engine the agent of civilization. I need hardly say that Watt's two chief inventions of the condenser and the expansive mode of working are simply two modes of economising heat. The double cylinder of Woolf, the method of surface-condensing, of super-heating, &c. are other inventions, directed to economy of coal. To save the loss of heat in the boiler, and the loss of power by friction, are two other points of economy, to which numberless inventions are directed. And with the exception of contrivances, such as the crank, the governor, and the minor mechanism of an engine, necessary for regulating, transmitting, or modifying its power, it may be said that the whole history of the steam-engine is one of economy.

"The economy of fuel is the secret of the economy of the steam-engine; it is the fountain of its power, and the adopted measure of its effects. Whatever, therefore, conduces to increase the efficiency of coal, and to diminish the cost of its use, directly tends to augment the value of the steam-engine, and to enlarge the field of its operations."4

The result of these efforts at economy is clearly exhibited in a table of the duty done by engines at different periods. This work or duty is expressed by the number of pounds of water raised one foot high by the expenditure of a bushel (84 lbs.) of coal.5

Year	(Technnology)	Duty in lbs
1769	Average of old atmospheric engines	5,590,000
1772	Smeaton's atmospheric engine	9,450,000
1776	Watt's improved engine	21,600,000
1779-1788	Watt's engine working expansively	26,600,000
1820	Engine improved by Cornish engineers	28,000,000
1830	Average duty of Cornish engines	43,350,000
1859	Average duty of Cornish engines	54,000,000
1859	Extreme duty of best engine	80,000,000

In less than one hundred years, then, the efficiency of the engine has been increased at least ten-fold; and it need hardly be said that it is the cheapness of the power it affords that allows us to draw rivers from our mines, to drive our coal-pits in spite of floods and quicksands, to drain our towns and lowlands, and to supply with water our highest places; and, finally, to put in motion the great system of our machine labour, which may be said, as far as any comparison is possible, to enable us to do as much as all the other inhabitants of the world with their unaided labours.

Future improvements of the engine can only have the same result, of extending the use of such a powerful agent. It is usual with a certain class of writers to depreciate science in regard to the steam-engine, and to treat this as a pure creation of practical sagacity. But just as the origin of the engine may be traced to a scientific work, so it is now theory and experiment in their highest and latest developments, which give us a sure notion how great will be the future improvement of the engine, and through what means it is to be aimed at.

Jdkag (talk) 08:10, 11 February 2010 (UTC)