Sylua syluarum: or A naturall historie In ten centuries. VVritten by the Right Honourable Francis Lo. Verulam Viscount St. Alban. Published after the authors death, by VVilliam Rawley Doctor of Diuinitie, late his Lordships chaplaine.

CONSENT OF VISIBLES, and Audibles.

[ 255] BOth of them spread themselues in Round, and fill a whole Floare or Orbe, vnto certaine Limits: And are carried a great way: And doe languish and lessen by degrees, according to the Distance of the Obiects from the Sensories.

[ 256] Both of them haue the whole Species in euery small Portion of the Aire, or Medium; So as the Species doe passe through small Crannies, without Confusion: As we see ordinarily in Leuels, as to the Eye; And in Cran∣nies, or Chinks, as to the Sound.

[ 257] Both of them are of a sudden and easie Generation and Delation; And likewise perish swiftly, and suddenly; As if you remoue the Light; Or touch the Bodies that giue the Sound.

[ 258] Both of them doe receiue and carry exquisite and accurate Differences; As of Colours, Figures, Motions, Distances, in Visibles; And of Articu∣late Voices, Tones, Songs, and Quauerings, in Audibles.

[ 259] Both of them in their Vertue and Working, doe not appeare to emit any Corporall Substance into their Mediums, or the Orbe of their Vertue; Neither againe to raise or stirre any euident locall Motion in their Mediums, as they passe; But only to carrry certaine Spirituall Species; The Perfect Knowledge of the Cause whereof, being hitherto scarcely attained, wee shall search and handle in due place.

[ 260] Both of them seeme not to generate or produce any other Effect in Na∣ture,

but such as appertaineth to their proper Obiects, and Senses, and are otherwise Barren.

But Both of them in their owne proper Action, doe worke three ma∣nifest [ 261] Effects. The First, in that the Stronger Species drawneth the E••sser; As the Light of the Sunne, the light of a Glow-worme; The Report of an Ordnance, the Voice; The Second, in that an Obiect of Surcharge or Excesse destroyeth the Sense; As the Light of the Sunne the Eye, a vio∣lent Sound (neare the Eare) the Hearing: The Third, in that both of them will be reuerberate; As in Mirrours; And in Eccho's.

Neither of them doth destroy or hinder the Species of the other, although [ 262] they encounter in the same Medium; As Light or Colour hinder not Sound; Nor ••contr••.

Both of them affect the Sense in Liuing Creatures, and yeeld Obiects of [ 263] Pleasure and Dislike: Yet neuerthelesse, the Obiects of them doe also (if it be well obserued) affect and worke vpon dead Things; Namely, such as haue some Conformity with the Organs of the two Senses; As Visibles worke vpon a Looking-glas∣se, which is like the Pupill of the Eye; And Audibles vpon the Places of Eccho, which resemble, in some sort, the Ca∣uerne and structure of the Eare.

Both of them doe diuersly worke, as they haue their Medium diuersly dis∣posed. [ 264] So a Trembling Medium (as Smoake) maketh the Obiect seeme to tremble; and a Rising or Falling Medium (as Winds) maketh the Sounds to rise, or fall.

To Both, the Medium, which it the most Prop••out•• and Conduci∣ble, [ 265] is Aire; For Glasse or Water, &c. are not comparable.

In Both of them, where the Obiect is Fine and Accurate, it conduceth [ 266] much to haue the Sense Intentiue, and Erect; In so much as you contract your Eye, when you would see sharply; And erect your Eare, when you would heare attentiuely; which in Beasts that haue Eares mouea∣ble, is most manifest.

The Beames of Light, when they are multiplyed, and conglomerate, ge∣nerate [ 267] Heat; which is a different Action, from the Action of Sight: And the Multiplication and Conglomeration of Sounds doth generate an ex∣treme Rarefaction of the Aire; which is an Action materiate, differing from the Action of Sound; If it be true (which is anciently reported) that Birds, with great shouts, haue fallen downe.