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HISTORICAL VIEW OF THE

they are called and raised to their apogee. These areall cases of action at a distance.” *

Under the second head, after remarking that everychange and motion requires time, he introduces thefollowing remarkable anticipation of subsequent dis-coveries : —

" The consideration of those things produced in mea doubt altogether astonishing ; viz. whether the face ofthe serene and starry heavens be seen at the instant itreally exists, or not till some time later; and whetherthere be not, with respect to the heavenly bodies, atrue time and an apparent time, no less than a trueplace and an apparent place, as astronomers say, on ac-count of parallax. For it seems incredible that thespecies, or rays of the celestial bodies, can pass throughthe immense interval between them and us in an instant,or that they do not even require some considerable por-tion of time.” + The actual measurement of thevelocity of light since effected, and the train of curiousconsequences deducible from it, are the best comment-aries on this passage, and the highest eulogy on itsautHor.

“ Instantise ostensivae,” which he also calls “ eluce-scentite” and “ predominantes,” are cases in whichsome particular quality is shown in its highest state ofpower and energy. In these cases such quality isfreed from the impediments which ordinarily impede orcounteract it, or predominates over others by which itis commonly confined or disguised. Bacon instancesthe thermometer, or vitrum calendare, as it was termed(then newly discovered), as exhibiting the expansivepower of heat in a magnified degree. We might ex-emplify it, perhaps, more perfectly in the Torricellianexperiment, by which the actual pressure of the at-mosphere is rendered manifest, though commonly dis-guised by its pressure in all directions.

“ Instantiae clandestine/’ also called “ instantis

* Novum Organon, ii. aph. 45.

t Id., it aph. 46.