“It now appeared that the cylinder of the model, being of brass, would conduct heat much better than the cast-iron cylinders of larger engines,”

— James Watt

"Notes on Professor Robison's Dissertation on Steam-engines" (1769)
Context: In the winter of 1763-4, having occasion to repair a model of Newcomen's engine belonging to the Natural Philosophy class of the University of Glasgow, my mind was again directed to it. At that period my knowledge was derived principally from Desaguliers, and partly from Belidor. I set about repairing it as a mere mechanician; and when that was done, and it was set to work, I was surprised to find that its boiler could not supply it with steam, though apparently quite large enough... By blowing the fire it was made to take a few strokes, but required an enormous quantity of injection water, though it was very lightly loaded by the column of water in the pump. It soon occurred that this was caused by the little cylinder exposing a greater surface to condense the steam, than the cylinders of larger engines did in proportion to their respective contents. It was found that by shortening the column of water in the pump, the boiler could supply the cylinder with steam, and that the engine would work regularly with a moderate quantity of injection. It now appeared that the cylinder of the model, being of brass, would conduct heat much better than the cast-iron cylinders of larger engines, (generally covered on the inside with a stony crust), and that considerable advantage could be gained by making the cylinders of some substance that would receive and give out heat slowly. Of these, wood seemed to be the most likely, provided it should prove sufficiently durable. A small engine was, therefore, constructed... made of wood, soaked in linseed oil, and baked to dryness. With this engine many experiments were made; but it was soon found that the wooden cylinder was not likely to prove durable, and that the steam condensed in filling it still exceeded the proportion of that required for large engines, according to the statements of Desaguliers. It was also found that all attempts to produce a better exhaustion by throwing in more injection, caused a disproportionate waste of steam. On reflection, the cause of this seemed to be the boiling of water in vacuo at low heats, a discovery lately made by Dr. Cullen and some other philosophers... and consequently at greater heats, the water in the cylinder would, produce a steam which would in part resist the pressure of the atmosphere.

Adopted from Wikiquote. Last update Nov. 1, 2024. History

Help us to complete the source, original and additional information

Do you have more details about the quote "It now appeared that the cylinder of the model, being of brass, would conduct heat much better than the cast-iron cylin…" by James Watt?

James Watt 7

British engineer 1736–1819

Related quotes

“Cézanne made a cylinder out of a bottle. I start from the cylinder to create a special kind of individual object. I make a bottle — a particular bottle — out of a cylinder.”

Juan Gris (1887–1927) Spanish painter and sculptor

Response to questionnaire circulated to the Cubists by Amédée Ozenfant and Le Corbusier, editors of L'Esprit Nouveau # 5 (February 1921), pp. 533-534; trans. Douglas Cooper in Daniel-Henry Kahnweiler, Juan Gris, His Life and Work (1947)

“On the train I was going over the problem of Sixes versus Fours and the disturbing periodic vibrations with which the 'six-cylinder manufacturers were contending. I realized the emphasis our competitors were placing on the fact that six smaller cylinders, producing the same maximum power as four larger ones, would result in smaller individual impulses, and consequent smoother action.
I knew that we were having good results with well-balanced four-cylinder motors. I first reasoned that if six light cylinders gave the same maximum power and lighter impulses than the tour, then eight still smaller cylinders would give still lighter impulses than the six cylinders. I also reasoned that, because of the lighter weight, those eight cylinder pistons could be run at higher speeds than either sixes or fours. Furthermore I did not like the six crankshaft. If made small enough to be in proportion with those light pistons, the extra length might introduce those undesirable vibrations; if made heavy enough to avoid; if made heavy enough to avoid these periodic vibrations there was the wight problem contend with.
As I lay awake pondering these factors, the idea came to me that we were having good success with four-cylinder motors; we would surely have equally good results with blocks of lighter four cylinders and pistons. Why not make up those smaller blocks of lighter four cylinders and pistons, and put two of the blocks together at an angle and avoid that troublesome long crankshaft. The more I thought of this idea on that trip, the more convinced I became that it could be worked out.”

Henry M. Leland (1843–1932) American businessman

Source: Master of Precision: Henry M. Leland, 1966, p. 147; Leland talking about his idea for a V8 engine around 1913-14. Partly cited in: Alexander Richard Crabb (1969), Birth of a giant: the men and incidents that gave America the motorcar. p. 315

“I have endeavoured to attain this end (viz. the production of a vacuum in the cylinder) in another way. As water has the property of elasticity, when converted into steam by heat, and afterwards of being so completely recondensed by cold, that there does not remain the least appearance of this elasticity, I have thought that it would not be difficult to work machines in which, by means of a moderate heat and at a small cost, water might produce that perfect vacuum which has vainly been sought by means of gunpowder.”

Denis Papin (1647–1713) French physicist, mathematician and inventor

Denis Papin, Recueil de diverses Pièces touchant quelques nouvelles Machines (1695) p. 53 as quoted by Dionysius Lardner, The Steam Engine Explained and Illustrated (1840) pp. 45-46

“The centre of gravity of any cylinder is the point of bisection of the axis.”

Archimedes book The Method of Mechanical Theorems

Proposition presumed from previous work.
The Method of Mechanical Theorems

“It is not given to a cylinder to move everywhere by its own motion,”

Marcus Aurelius book Meditations

X, 33
Meditations (c. 121–180 AD), Book X
Context: It is not given to a cylinder to move everywhere by its own motion, nor yet to water nor to fire nor to anything else which is governed by nature or an irrational soul, for the things which check them and stand in the way are many. But intelligence and reason are able to go through everything that opposes them, and in such manner as they are formed by nature and as they choose. Place before thy eyes this facility with which the reason will be carried through all things, as fire upwards, as a stone downwards, as a cylinder down an inclined surface, and seek for nothing further. For all other obstacles either affect the body only, which is a dead thing; or, except for opinion and the yielding of reason itself, they do not crush nor do any harm of any kind; for if they did, he who felt it would immediately become bad.