A Preliminary Discourse on the Study of Natural PhilosophyLongman, Brown, Green & Longmans, 1851 - 372 pàgines |
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A Preliminary Discourse on the Study of Natural Philosophy John Frederick William Herschel Visualització completa - 1831 |
A Preliminary Discourse on the Study of Natural Philosophy John Frederick William Herschel Visualització completa - 1840 |
A Preliminary Discourse on the Study of Natural Philosophy John Frederick William Herschel Visualització completa - 1832 |
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abstract action actual afford analogy appear application ascer ascertained astronomy become bodies branch of science cause character chemical chemical elements chemistry circumstances colours combinations conclusions consequences consider deductive reasoning degree determination dilatation direct discovery distinct double refraction duction earth effect elastic electricity enabled enquiry error evidence exact exer existence experience facts fluid force Galileo heat important impression induction influence instance kind knowledge laws of nature least less light liquids magnetism mass material mathematical matter means measure mechanism ment mind mineralogy mode motion mutual natural philosophy Newton objects observation once particles particular peculiar perceive pheno phenomena phenomenon philosopher planets present principle of repetition principles produced proportion quantity racters reasoning refraction regarded relations remarkable repulsive scurvy sense sensible sidered solid speculation stances standard atomic weights substances surface theory thing tion tricity truth tural vera causa verification weight whole
Passatges populars
Pàgina 114 - ... single and perfectly definite new circumstance, and manifesting the effect so rapidly that there is not time for any other material change in the pre-existing circumstances. " It is observed that dew is never copiously deposited in situations much screened from the open sky, and not at all in a cloudy night ; but if the clouds...
Pàgina 266 - Man's progress towards a higher state need never fear a check, but must continue till the very last existence of history.
Pàgina 110 - Many of the new elements of chemistry have been detected in the investigation of residual phenomena. Thus Arfwedson discovered lithia by perceiving an excess of weight in the sulphate produced from a small portion of what he considered as magnesia present in a mineral he had analyzed.
Pàgina 60 - ... and by a proper adaptation of means, is of itself sufficient to set us earnestly on reflecting what ends are truly great and noble, either in themselves, or as conducive to others of a still loftier character ; because we are not now, as heretofore, hopeless of attaining them.
Pàgina 6 - Deity on such grounds as to render doubt absurd and atheism ridiculous, it unquestionably opposes no natural or necessary obstacle to further progress: on the contrary, by cherishing as a vital principle an unbounded spirit of inquiry, and ardency of expectation, it unfetters the mind from prejudices of every kind, and leaves it open and free to every impression of a higher nature which it is susceptible of receiving, guarding only against enthusiasm and self-deception by a habit of strict investigation,...
Pàgina 229 - geology, in the magnitude and sublimity of the objects of which it treats, undoubtedly ranks, in the scale of the sciences, next to astronomy...
Pàgina 56 - ... of millions. Those who admire and love knowledge for its own sake, ought to wish to see its elements made accessible to all, were it only that they may be the more thoroughly examined into, and more effectually developed in their consequences, and receive that ductility and plastic quality which the pressure of minds of all descriptions, constantly moulding them to their purposes, can alone bestow.
Pàgina 10 - ... beings, many thousands of whose bodies, laid close together, would not extend an inch? But what are these to the astonishing truths which modern optical inquiries have disclosed, which teach us, that every point of a medium through which a ray of light passes is affected with a succession of periodical movements, regularly recurring, at equal intervals, no less than 500 millions of millions of times in a single second!
Pàgina 127 - The formulae," says Sir John Herschel,* " which have been empirically deduced for the elasticity of steam (till very recently), and those for the resistance of fluids, and other similar subjects," when relied on beyond the limits of the observations from which they were deduced, " have almost invariably failed to support the theoretical structures which have been erected on them.
Pàgina 36 - Between the physical sciences and the arts of life there subsists a constant mutual interchange of good offices, and no considerable progress can be made in the one without of necessity giving rise to corresponding steps in the other. On the one hand, every art is in some measure, and many entirely, dependent on those very powers and qualities of the material world which it is the object of physical inquiry to investigate and explain...