“The Posthumous Works of Robert Hooke M. D.,'… appeared in 1705, containing 'A Discourse of Earthquakes'… His treatise… is the most philosophical production of that age, in regard to the causes of former changes in the organic and inorganic kingdoms of nature. 'However trivial a thing,' he says, 'a rotten shell may appear to some, yet these monuments of nature are more certain tokens of antiquity than coins or medals, since the best of those may be counterfeited or made by art and design, as may also books, manuscripts, and inscriptions, as all the learned are now sufficiently satisfied has often been actually practised,' &c.; 'and though it must be granted that it is very difficult to read them and to raise a chronology out of them, and to state the intervals of the time wherein such or such catastrophes and mutations have happened, yet it is not impossible.”

Section IX, "Man Alone with Himself" / aphorism 513
Human, All Too Human (1878), Helen Zimmern translation

The Patriot (1774)

A Preliminary Discourse on the Study of Natural Philosophy (1831)
Context: We must never forget that it is principles, not phenomena, — laws not insulated independent facts, — which are the objects of inquiry to the natural philosopher. As truth is single, and consistent with itself, a principle may be as completely and as plainly elucidated by the most familiar and simple fact, as by the most imposing and uncommon phenomenon. The colours which glitter on a soapbubble are the immediate consequence of a principle the most important, from the variety of phenomena it explains, and the most beautiful, from its simplicity and compendious neatness, in the whole science of optics. If the nature of periodical colours can be made intelligible by the contemplation of such a trivial object, from that moment it becomes a noble instrument in the eye of correct judgment; and to blow a large, regular, and durable soap-bubble may become the serious and praise-worthy endeavour of a sage, while children stand round and scoff, or children of a larger growth hold up their hands in astonishment at such waste of time and trouble. To the natural philosopher there is no natural object unimportant or trifling. From the least of nature's works he may learn the greatest lessons. The fall of an apple to the ground may raise his thoughts to the laws which govern the revolutions of the planets in their orbits; or the situation of a pebble may afford him evidence of the state of the globe he inhabits, myriads of ages ago, before his species became its denizens.
And this, is, in fact, one of the great sources of delight which the study of natural science imparts to its votaries. A mind which has once imbibed a taste for scientific inquiry, and has learnt the habit of applying its principles readily to the cases which occur, has within itself an inexhaustible source of pure and exciting contemplations. One would think that Shakspeare had such a mind in view when he describes a contemplative man as finding

"Rules of Reasoning in Philosophy" : Rule I
Philosophiae Naturalis Principia Mathematica (1687)

Speech on the American Civil War, Town Hall, Newcastle upon Tyne (7 October 1862), quoted in The Times (9 October 1862), pp. 7-8.
1860s

Book III, Ch. IV, pp. 152-155.
Physics

Source: Guide for the Perplexed (c. 1190), Part III, Ch.25

Notes of Six Lectures on Landscape Painting (1836), C.R. Leslie, Memoirs of the Life of John Constable (1843), p. 343
1830s, his lectures History of Landscape Painting (1836)

Source: Dictionary of Burning Words of Brilliant Writers (1895), P. 190.