The Development of Science and Technology in Nineteenth-Century Britain

The Importance of Manchester

Donald Cardwell, Richard Hills

• Publisher: Routledge
• Year: 2017
• ISBN:
  9781351728843
• Edition: 1
• Topic: History
• Subtopic: World History
• Index: History

This title was first published in 2003. Donald Cardwell's interest in the inter-relationships between science, technology, education and society are exemplified in the selection of his studies and essays brought together here. The first section deals with the rise of scientific education in Britain, comparing it with that on the Continent. The next studies explore the development of the scientific understanding of power, especially steam power, and its application in the new technologies of the Industrial Revolution. The final section looks at learned societies, and in particular at Manchester, making explicit a theme running through many of the articles - the reasons why science, society and education came together to make this city what he called 'the centre of the industrial revolution'.

VI
Power Technologies and the Advance of Science, 1700–1825

The science of thermodynamics was one of the major intellectual achievements of the nineteenth century, and the origins of its basic principles must therefore be of great interest to the historian. The first two principles to be established were the statement of the mechanical equivalence of heat (Mayer and Joule) and the postulation by Sadi Carnot of an idealized heat engine which, when working in a precisely specified manner on a cycle that can be performed in the inverse sense, must obtain the maximum possible work from a given "fall" of heat from a furnace to a cold body, or condenser.¹ Carnot noticed that the cold body is as necessary for the production of work as the furnace: he thus imposed in advance an important limitation on the then unformulated doctrine of the mechanical equivalence of heat: work can be obtained only when heat flows from a hot to a cold body.

It is hardly less important for the historian of science and technology to have some idea of the circumstances that led to the formulation of the concepts of the ideal heat engine and the reversible cycle than it is for him to understand the development, in the seventeenth century, of the concepts of mass and force. There is, in the former case, the added interest that the source of the concepts was unquestionably technological, and this constitutes a very serious objection to the theory that the development of "pure" science owes little or nothing to technology. Also, it might be argued that, unless there is some account of the technological factors, the concepts of thermodynamics, as described in standard works on heat, must seem to be curiously arbitrary inventions.

The purpose of this paper is twofold: first, to discuss the relationship between the two main power technologies and the advance of science during the period 1700-1825, and, second, to try to see what light this throws on Carnot's great work. Carnot himself provides the

Dr. Cardwell, Reader in the History of Science and Technology at Manchester College of Science and Technology, is the author of Steam Power in the Eighteenth Century and Organisation of Science in England. justification for this, for he wrote that while engines driven by water, air, or animal power could be completely analyzed by mechanical theory, a similar theory for the study of heat engines was conspicuously lacking.² He was stimulated, that is, by the prior achievements of the science of mechanics in rationalizing the other power technologies.

Power Technologies in the Eighteenth Century

Machines are not discrete or isolated models, but members of family groups, of species, and of genera. The various related groups correspond to human wants—and to human ingenuity in satisfying those wants. It is, of course, true that only a few species may ultimately survive the competitive struggle to give rise to other and improved types. But, in the histories of science and technology, the unsuccessful and the superseded often deserve study, for they may well have stimulated or influenced the successful in ways which we have now forgotten or overlooked.

Steam Power

About eight different families of heat engines were developed in this period. They met with different degrees of success.

1. Steam wheels.—A hollow wheel having hollow spokes fitted with suitable valves and containing a mixture of vapor and liquid is heated on one side; the vapor pressure increases and forces the liquid to the other side, the resulting imbalance causing the wheel to rotate. The first steam wheel was invented by Amontons in 1699. James Watt later experimented with a form of this engine.

2. Savery engines.—These were rapidly superseded by the atmospheric engine and the steam engine.

3. The Newcomen atmospheric engine.— This and, later, its descendant, the conventional steam engine, in which steam pressure acts on a piston moving in a tight cylinder, superseded the Savery engine. James Watt was, of course, the pioneer of the (low-pressure) steam engine.

4. Buoyancy engines.—These were almost the converse of the steam wheel. Suspended up to the axle in a heated liquid, a "bucket" wheel is rotated by the buoyancy of bubbles of air, steam, or other vapor or gas rising through the liquid and being collected in the downward-facing buckets. When the vapor is not produced by actually boiling the liquid, the added buoyancy resulting from the expansion of the heated vapor will provide the extra power needed to pump the initially cold vapor down to the correct depth in the liquid. On the one hand, these engines could use low-temperature heat, often a waste product of industrial processes; on the other hand, their drawbacks are obvious. Engines of this type were invented from about 1790 onward.³

In an interesting paper Professor Thomas S. Kuhn has recently suggested that one of these engines, invented by Cagnard Latour in 1809, may have inspired Carnot's ideas.⁴ It is a "heat" engine, independent of change of state (vaporization) and, in Cagnard Latour's version, it uses air as a working substance. But, being continuously rotative, its action does not at once suggest cyclic operation, and it is not easy to see how the desideratum of operation in the inverse sense could be inferred from it. Also, we may wonder whether ideas of such general application as Carnot's could have been inspired by one particular engine, and that a comparatively inefficient one.

5. Direct rotative engines.— These were invented first by Watt. Of two concentric drums, the inner, or movable one, is fitted with a flat radial paddle or vane, equivalent to a piston, which moves in the annular space between the drums; the outer, fixed drum carries a retractable baffle which normally just touches the inner one. The connections to the boiler and to the condenser are on opposite sides of the baffle so that the injected steam acts on one side of the vane only.⁵ Although popular with inventors, this engine was never successful; the problem of rapidly withdrawing the baffle into the outer drum to allow the vane to pass it once every revolution was never satisfactorily solved. These engines were not, of course, anticipations of the steam turbine.

In 1816, A. R. Bouvier, a French engineer, discovered, apparently quite independently, the principle of the expansive use of steam. He thought that invention had done as much as it possibly could do for the improvement of the steam engine and that further progress could only be made by the systematic application of mathematics and physics. So, ignoring all the great practical difficulties, he proposed a rotative engine working on the expansive principle as a kind of theoretically ideal engine to which scientific analysis could be applied.⁶ This foreshadows, to some extent, the ideal heat engine; and, if Carnot knew of it, it may have had some effect on the development of his thought.

6. Simple reaction and impulse engines.—These engines work on the principle of the old aeolopile and of Branca's wheel (seventeenth century) respectively.

7. Attempts to harness the apparently irresistible expansion of liquids and solids.—A common factor in all these inventions and developments was the systematic improvement in engineering skills in the course of the eighteenth century. The most notable advance was probably in the ability to use steam at progressively higher pressures, thus enabling smaller and more efficient engines to be built. The high-pressure steam engine began to appear in the late 1790's, having been introduced simultaneously by Oliver Evans and Richard Trevithick. James Watt, the fastidious genius, played an important part in the attainment of great engineering skills. And, through his superb insight into the physics of gases he early realized the importance of the expansive use of steam.⁷ This practice greatly expedited the development of the high-pressure steam engine.

Water Power

In a very well-known passage Carnot observes:

D'après les notions établies jusqu'à présent, on peut comparer avec assez de justesse la puissance motrice de la chaleur à celle d'une chute d'eau: tout deux ont un maximum que l'on ne peut dépasser quelle que soit d'une part la machine employée à recevoir l'action de l'eau, et quelle que soit de l'autre la substance employée à recevoir l'action de la chaleur.⁸

He seeks analogies from water-power technology for the development of his ideas on heat engines: to temperature corresponds the head of water, or height of fall; to quantity of heat corresponds quantity of water. And, since the impossibility of perpetual motion imposes an upper limit on the power to be obtained from a given fall of water, Carnot infers that the same consideration must limit the power available from a given "fall of caloric." Indeed, the only difficulty in the whole passage is the translation—or interpretation—of the French word "machine." Can we assume, as most writers appear to do, that its full significance is conveyed by the word "waterwheel"? To answer this question we shall have to examine the development of water-power technology and its related sciences during this period. This may help us to understand the analogues that Carnot evidently had in mind.

We must note that water power was by no means a "finished art": between 1700 and 1825 it underwent radical transformation, being converted from a traditional craft into a scientific technology. In England the important first stages of the Industrial Revolution, at least in textile industries, were achieved almost entirely on water power: as late as 1800 much the greater part of the power used by the Lancashire, Cheshire, and Yorkshire mills was provided by water.⁹ The first great mills were not driven by traditional craft-made wheels but by accurately designed machines based on new scientific ideas. During the period 1700-1825 water- and heat-power technologies advanced pari passu. They were of critical economic importance for the textile and mining industries, and both held great promise of further development. We should naturally expect that two such closely related technologies would greatly influence one another, that there would be a considerable degree of cross-fertilization between them, as is characteristic of cognate sciences and technologies.

Classical mechanics, although admirably adapted for solving such problems of accelerated motion as the behavior of planets and satellites, did not lend itself readily to the study of the power obtainable from unaccelerated machines. To Antoine Parent belongs the credit for opening, in 1704, the scientific discussion of this question in its application to waterwheels.¹⁰ He concluded that the wheel should move at one-third the velocity of the stream if the maximum power was to be developed, but that this power could never exceed 4/27 of that resident in the moving water. He had biased the issue, probably unwittingly, by considering "undershot" wheels only, and his analysis was defective in that he assumed that only one blade was immersed at any given time. This led him to conclude that the mass of water striking the wheel in unit time varied with the relative velocity. There was no idea of anything lost in the turbulent impact of water on blade: of, as we should say, kinetic energy lost in an inelastic collision. Nevertheless, Parent's conclusions were generally accepted, and many took 4/27 to represent the maximum power for all waterwheels under all condi-tions.¹¹

By mid-century, however, it had become clear to the scientific engineers Deparcieux in France and Smeaton in England that, in practice, waterwheels could yield appreciably more than the accepted limit. Deparcieux, in fact, put forward in 1754 the concept of a mechanically perfect overshot (bucket) wheel driving an identical wheel backward.¹² The more water that this combination lifted, or pumped back, the slower the two coupled wheels would turn until, at very slow speed, practically all the driving water is pumped back and the theoretical limit approached is one. Beyond this one cannot go. Deparcieux could not, of course, produce models perfect enough to approach this limit, but he did offer, in true Galilean fashion, experimental evidence in confirmation. He showed that the speed with which a heavier weight will lift a lighter weight, to which it is joined by a thin thread passing over a nearly frictionless pulley, diminishes as the lighter weight is made more equal to the heavier one; that is, as the limit of one is approached. In this way Deparcieux demonstrated that an overshot wheel, worked by the weight of descending water, could be considerably more efficient than 4/27, the accepted maximum for a wheel driven by the impact of moving water.

Here we have postulated as the ideal a machine able to work in the inverse sense and so to restore the status quo ante; a "thought model" at the very outset of the scientific study of water power. From this time onward French writers justifiably took Deparcieux's paper as a fundamental contribution to water-power technology.

Smeaton, a most able engineer, demonstrated with experimental models that, other things being equal, the same wheel was twice as efficient overshot as undershot, and he conf...

Table of contents

• Cover
• Half Title
• Title
• Copyright
• Contents
• Foreword
• Acknowledgements
• Donald Stephen Lowell Cardwell
• Select Bibliography
• SCIENCE, TECHNOLOGY AND EDUCATION
• POWER TECHNOLOGIES, THERMODYNAMICS AND ELECTRICITY
• THE IMPORTANCE OF MANCHESTER
• Index of People
• General Index