William John Macquorn Rankine Quotes (28 quotes)

"On the Harmony of Theory and Practice in Mechanics" (Jan. 3, 1856)
Context: The evil influence of the supposed inconsistency of theory and practice upon speculative science, although much less conspicuous than it was in the ancient and middle ages, is still occasionally to be traced. This it is which opposes the mutual communication of ideas between men of science and men of practice, and which leads scientific men sometimes to employ, on problems that can only be regarded as ingenious mathematical exercises, much time and mental exertion that would be better bestowed on questions having some connection with the arts, and sometimes to state the results of really important investigations on practical subjects in a form too abstruse for ordinary use; so that the benefit which might be derived from their application is for years lost to the public; and valuable practical principles which might have been anticipated by reasoning, are left to be discovered by slow and costly experience.<!--pp. 175

“Some of the evils which are caused by the fallacy of an incompatibility between theory and practice having been described, it must now be admitted, that at the present time those evils show a decided tendency to decline. The extent of intercourse, and of mutual assistance, between men of science and men of practice, the practical knowledge of scientific men, and the scientific knowledge of practical men, have been for some time steadily increasing; and that combination and harmony of theoretical and practical knowledge—that skill in the application of scientific principles to practical purposes, which in former times was confined to a few remarkable individuals, now tends to become more generally diffused.”

William John Macquorn Rankine

p, 125
"On the Harmony of Theory and Practice in Mechanics" (Jan. 3, 1856)

“A physical theory, like an abstract science, consists of definitions and axioms as first principles, and of propositions, their consequences; but with these differences:—first, That in an abstract science, a definition assigns a name to a class of notions derived originally from observation, but not necessarily corresponding to any existing objects of real phenomena, and an axiom states a mutual relation amongst such notions, or the names denoting them; while in a physical science, a definition states properties common to a class of existing objects, or real phenomena, and a physical axiom states a general law as to the relations of phenomena; and, secondly,—That in an abstract science, the propositions first discovered are the most simple; whilst in a physical theory, the propositions first discovered are in general numerous and complex, being formal laws, the immediate results of observation and experiment, from which the definitions and axioms are subsequently arrived at by a process of reasoning differing from that whereby one proposition is deduced from another in an abstract science, partly in being more complex and difficult, and partly in being to a certain extent tentative, that is to say, involving the trial of conjectural principles, and their acceptance or rejection according as their consequences are found to agree or disagree with the formal laws deduced immediately from observation and experiment.”

William John Macquorn Rankine

Source: "Outlines of the Science of Energetics," (1855), p. 121; Second paragraph

William John Macquorn Rankine Quotes about knowledge

“The objects of instruction in purely scientific mechanics and physics are, first, to produce in the student that improvement of the understanding which results from the cultivation of natural knowledge, and that elevation of mind which flows from the contemplation of the order of the universe”

William John Macquorn Rankine

"On the Harmony of Theory and Practice in Mechanics" (Jan. 3, 1856)
Context: The objects of instruction in purely scientific mechanics and physics are, first, to produce in the student that improvement of the understanding which results from the cultivation of natural knowledge, and that elevation of mind which flows from the contemplation of the order of the universe; and secondly, if possible, to qualify him to become a scientific discoverer.<!--p. 176

“Mechanical knowledge may… be distinguished into three kinds; purely scientific knowledge, purely practical knowledge, and that intermediate kind of knowledge which relates to the application of scientific principles to practical purposes, and which arises from understanding the harmony of theory and practice.”

William John Macquorn Rankine

"On the Harmony of Theory and Practice in Mechanics" (Jan. 3, 1856)

“Another evil, and one of the worst which arises from the separation of theoretical and practical knowledge, is the fact that a large number of persons”

William John Macquorn Rankine

"On the Harmony of Theory and Practice in Mechanics" (Jan. 3, 1856)
Context: Another evil, and one of the worst which arises from the separation of theoretical and practical knowledge, is the fact that a large number of persons, possessed of an inventive turn of mind and of considerable skill in the manual operations of practical mechanics, are destitute of that knowledge of scientific principles which is requisite to prevent their being misled by their own ingenuity. Such men too often spend their money, waste their lives, and it may be lose their reason in the vain pursuits of visionary inventions, of which a moderate amount of theoretical knowledge would be sufficient to demonstrate the fallacy; and for want of such knowledge, many a man who might have been a useful and happy member of society, becomes a being than whom it would be hard to find anything more miserable.
The number of those unhappy persons — to judge from the patent-lists, and from some of the mechanical journals — must be much greater than is generally believed.<!--p. 176

William John Macquorn Rankine Quotes

“In treating of the practical application of scientific principles, an algebraical formula should only be employed when its shortness and simplicity are such as to render it a clearer expression of a proposition or rule than common language would be, and when there is no difficulty in keeping the thing represented by each symbol constantly before the mind.”

William John Macquorn Rankine

"On the Harmony of Theory and Practice in Mechanics" (Jan. 3, 1856)
Context: In treating of the practical application of scientific principles, an algebraical formula should only be employed when its shortness and simplicity are such as to render it a clearer expression of a proposition or rule than common language would be, and when there is no difficulty in keeping the thing represented by each symbol constantly before the mind.<!--p. 177

“The ascertainment and illustration of truth are the objects; and structures and machines are looked upon merely as natural bodies”

William John Macquorn Rankine

"On the Harmony of Theory and Practice in Mechanics" (Jan. 3, 1856)
Context: The ascertainment and illustration of truth are the objects; and structures and machines are looked upon merely as natural bodies are; namely, as furnishing experimental data for the ascertaining of principles and examples for their application.<!--p. 176

Truth , Nature

“The most absurd of all their delusions commonly called the, or to speak more accurately, the inexhaustible source of power—is, in various forms, the subject of several patents in each year.”

William John Macquorn Rankine

"On the Harmony of Theory and Practice in Mechanics" (Jan. 3, 1856), p. 176

“In thermodynamics as well as in other branches of molecular physics, the laws of phenomena have to a certain extent been anticipated, and their investigation facilitated, by the aid of hypotheses as to occult molecular structures and motions with which such phenomena are assumed to be connected.”

William John Macquorn Rankine

Source: A Manual of the Steam Engine and Other Prime Movers (1859), p. 31
Context: Hypothesis Of Molecular Vortices. In thermodynamics as well as in other branches of molecular physics, the laws of phenomena have to a certain extent been anticipated, and their investigation facilitated, by the aid of hypotheses as to occult molecular structures and motions with which such phenomena are assumed to be connected. The hypothesis which has answered that purpose in the case of thermodynamics, is called that of "molecular vortices," or otherwise, the "centrifugal theory of elasticity. (On this subject, see the Edinburgh Philosophical Journal, 1849; Edinburgh Transactions, vol. xx.; and Philosophical Magazine, passim, especially for December, 1851, and November and December, 1855.)

Law

“But a class of structures fraught with much greater evils exist in great abundance throughout the country—namely, those in which the faults of an unscientific design have been so far counteracted by massive strength, good materials, and careful workmanship, that a temporary stability has been produced, but which contain within themselves sources of weakness, obvious to a scientific examination… that must inevitably cause their destruction within a limited number of years.”

William John Macquorn Rankine

p, 125
"On the Harmony of Theory and Practice in Mechanics" (Jan. 3, 1856)

Evil , Country

“In theoretical science, the question is—What are we to think? and when a doubtful point arises, for the solution of which either experimental data are wanting, or mathematical methods are not sufficiently advanced, it is the duty of philosophic minds not to dispute about the probability of conflicting suppositions, but to labour for the advancement of experimental inquiry and of mathematics, and await patiently the time when they shall be adequate to solve the question.”

William John Macquorn Rankine

p, 125
"On the Harmony of Theory and Practice in Mechanics" (Jan. 3, 1856)

Mathematics , Question , Thinking , Science

“The third and intermediate kind of instruction, which connects the first two… relates to the application of scientific principles to practical purposes. It qualifies the student to plan a structure or a machine for a given purpose, without the necessity of copying some existing example, and to adapt his designs to situations to which no existing example affords a parallel. It enables him to compute the theoretical limit of the strength or stability of a structure, or the efficiency of a machine of a particular kind—to ascertain how far an actual structure or machine fails to attain that limit—to discover the cause of such shortcomings—and to devise improvements for obviating such causes; and it enables him to judge how far an established practical rule is founded on reason, how far on mere custom, and how far on error.”

William John Macquorn Rankine

p, 125
"On the Harmony of Theory and Practice in Mechanics" (Jan. 3, 1856)

Error

“Discrepancy between theory and practice, which in sound physical and mechanical science is a delusion, has a real existence in the minds of men; and that fallacy, through rejected by their judgments, continues to exert and influence over their acts.”

William John Macquorn Rankine

"Introductory Lecture on the Harmony of Theory and Practice in Mechanics" (1856), p. 4

Men , Science

“The hypothesis of molecular vortices is defined to be that which assumes — that each atom of matter consists of a nucleus or central point enveloped by an elastic atmosphere, which is retained in its position by attractive forces, and that the elasticity due to heat arises from the centrifugal force of those atmospheres revolving or oscillating about their nuclei or central points.
According to this hypothesis, quantity of heat is the vis viva of the molecular revolutions or oscillations.”

William John Macquorn Rankine

"On the Centrifugal Theory of Elasticity as applied to Gases and Vapours" in The London, Edinburgh and Dublin Philosophical Magazine and Journal of Science (July-December 1851), p. 510

“But in practical science, the question is—What are we to do?—a question which involves the necessity for the immediate adoption of some rule of working. In doubtful cases, we cannot allow our machines and our works of improvement to wait for the advancement of science; and if existing data are insufficient to give an exact solution of the question, that approximate solution must be acted upon which the best data attainable show to be the most probable. A prompt and sound judgment in cases of this kind is one of the characteristics of a Practical Man in the right sense of that term.”

William John Macquorn Rankine

p, 125
"On the Harmony of Theory and Practice in Mechanics" (Jan. 3, 1856)

Question , Sense , Science , Waiting

“[T]he symbols of algebra, when employed in abstruse and complex theoretical investigations, constitute a sort of thought-saving machine, by whose aid a person skilled in its use can solve problems respecting quantities, and dispense with the mental labour of thinking of the quantities denoted by the symbols, except at the beginning and the end of the operation.”

William John Macquorn Rankine

p, 125
"On the Harmony of Theory and Practice in Mechanics" (Jan. 3, 1856)

Problem , Thinking , Personality

“It is possible to express the laws of thermodynamics in the form of independent principles, deduced by induction from the facts of observation and experiment, without reference to any hypothesis as to the occult molecular operations with which the sensible phenomena may be conceived to be connected; and that course will be followed in the body of the present treatise. But, in giving a brief historical sketch of the progress of thermodynamics, the progress of the hypothesis of thermic molecular motions cannot be wholly separated from that of the purely inductive theory.”

William John Macquorn Rankine

Source: A Manual of the Steam Engine and Other Prime Movers (1859), p. 27

Law

William John Macquorn Rankine

The extent of intercourse, and of mutual assistance, between men of science and men of practice, the practical knowledge of scientific men, and the scientific knowledge of practical men, have been for some time steadily increasing; and that combination and harmony of theoretical and practical knowledge—that skill in the application of scientific principles to practical purposes, which in former times was confined to a few remarkable individuals, now tends to become more generally diffused.
"On the Harmony of Theory and Practice in Mechanics" (Jan. 3, 1856)

Time , Evil