Full text: Barrow, Isaac: Lectiones Opticæ & Geometricæ

CB exiſtet; ſin AE & lt; AN, punctum Z verſus π exiſtet; ſin
AE = AN; concurſus infinitè diſtabit; ſeu proximus reflexus ipſi
N π parallelus erit.

19.1.

Fig. 106.

Not. ductâ AQ ad CB perpendiculari, ſi AE = AN; erit
AN = √{AQ q/3}. Nam AQ q = AP x AN = 3 AN x AN = 3 AN x AN
= 3 ANq; itaque punctum N, iſtos caſus diſterminans, facilè de-
ſignatur.

19.1.

Fig. 106.

Rationem ipſi tantillùm attendentes perſpicietis; mihi ſanè cunctas
evolvendo minutias non animi ſatìs, non otii ſuppetit.

XXVIII. Juvabit his unam, loco forſan opportuniore prætermiſſam,
obſervatiunculam attexere. Si fuerit Z radiantis A lmago, viciſſim erit
A radiantis Z lmago. è dictis quoad ſpeciales caſus facilè cernitur
hoc conſectari. quin & hinc generatim verum apparebit ſatìs: Si fue-
rit Z ipſius A imago, tantum unus idcircò ab A manantium inflexus
per Z tranſibit. (hoc imagini proprium eſſe ſæpiùs in decurſu in-
culcata ſatìs arguunt, ſuperque) quare reciprocè ſolus unus ab Z
manantium inflexus per A tranlibit (nam ſi duo tales per A tranſire
dicantur, etiam indè duo per Z tranſibunt, contra hypotheſin) erit
igitur A ipſius Z imago. Merebatur hæc (compendio bene ſerviens,
& caſus inter ſe varios conferentibus affundens lucem) obſervatio gene-
ralibus intertexi; niſi quòd non omnia ſe nobis ſtatim produnt; & quædam in abſtractione ſumma non ità facilè vèl explicari poſſunt,
vel comprobari.

A Catoptricis jam aliquando manum. quæ contentus ità quadante-
nus promoviſſe, haud diſparia (certè magìs nova, miniméque pro-
trita) circa refractiones ſphæricas, ſeu circulares, attentabo.

Waiting...

Note to user

Dear user,

In response to current developments in the web technology used by the Goobi viewer, the software no longer supports your browser.

Please use one of the following browsers to display this page correctly.

Thank you.

powered by Goobi viewer