subtile

Recent scientific discoveries have conferred upon man new powers of investigation, whereby nature has been made to reveal secrets so subtile that they never had been dreamt of before in philosophy.

From Scientific American ● Jan. 13, 2013

At Paris the Universe is seen, compos’d of Vortices of subtile Matter; but nothing like it is seen in London.

From "The Invention of Science" by David Wootton

Every one is the symbol of wisdom, and hath, in its malic acid, a subtile essence, which carries health to the morbid liver.

From A Breeze from the Woods, 2nd Ed. by William Chauncey Bartlett

Sub′tilism, the quality of being subtile; Sub′tilty, state or quality of being subtile: fineness: extreme acuteness: cunning.

From Chambers's Twentieth Century Dictionary (part 4 of 4: S-Z and supplements) by Various

He will come very near to us in his books, and by that subtile law of communion which, through the brightest and noblest utterances, makes all the better world akin.

From A Breeze from the Woods, 2nd Ed. by William Chauncey Bartlett

Bread is a binder, and for that abolisht even in their Ale, whose lost room fills an apple, which is more airy and of subtiler nature.

From The Scornful Lady by John Fletcher

No, his temperament needed a subtiler atmosphere than this, rarer essence than mere brutal freedom The East, the Old World, was his proper sphere for self-development.

From Margret Howth, a Story of To-day by Rebecca Harding Davis

Is not the Heat of the warm Room convey'd through the Vacuum by the Vibrations of a much subtiler Medium than Air, which after the Air was drawn out remained in the Vacuum?

From Opticks or, a Treatise of the Reflections, Refractions, Inflections, and Colours of Light by Sir Isaac Newton

Something keener than philosophy, subtiler than Epicurus, pricked Fred, as Minnie vanished into the cloud of snowflakes.

From The Atlantic Monthly, Volume 03, No. 18, April, 1859 by Various

That cause of motion he makes the Materia Subtilis; and the finer or subtiler that is, the better and fitter he conceives it to be to preserve Motion.

From Philosophical Transactions of the Royal Society - Vol 1 - 1666 Giving some Accompt of the present Undertakings, Studies, and Labours of the Ingenious in many considerable parts of the World by Henry Oldenburg

The notion of nonentity may thus be called the parent of the philosophic craving in its subtilest and profoundest sense.

From The Will to Believe : and Other Essays in Popular Philosophy by William James

Truth is a point; the subtilest and finest; harder than adamant; never to be broken, worn away, or blunted.

From Imaginary Conversations and Poems A Selection by Walter Savage Landor

This is a truth that takes all the sting out of Lord Bacon's observation that "against Atheists the very savages take part with the very subtilest philosophers."

From Flowers of Freethought (Second Series) by G. W. (George William) Foote

Said to us, during the past season, the subtilest thinker of Great Britain,—"I must send to America whatever I wish to put in print, unless I pay for its publication from my own pocket."

From The Atlantic Monthly, Volume 02, No. 12, October, 1858 by Various

She took yellow honeysuckles from a vase of massed amethyst and began to weave them in her yellow hair,—humming a tune, the while, that was full of the subtilest curves of sound.

From The Atlantic Monthly, Volume 11, No. 67, May, 1863 by Various