Full text: Barrow, Isaac: Lectiones Opticæ & Geometricæ

_XI._ Ad lentem convexo-convexam diverg.

Fig. 158,

_XII._ Ad lentem concavo-concavam converg.

1. Si AB & gt; {R/I} AC, facto AB - {R/I} AC. AB : : BC. BZ; & {I/R} KZ - DZ : : DK. DY; puncta Z, Y adverſus Acadunt.

2. Si AB = {R/I} AC, fac I - R. R : : DK. DY; & cape DY
adverſus A.

3. Si AB & lt; {R/I} AC; fac {R/I} AC - AB. AB : : BC. BZ; & ſume BZ verſus A. Jam cùm Z cadit extra DK, ſi primò ſit
{I/R} KZ & gt; DZ, fac {I/R} KZ - DZ. DZ : : DK. DY; & ſume
DY adverſus A

4. Secundò, ſi {I/R} KZ = DZ, imago diſtabit infini è.

5. Tertiò, ſi {I/R} KZ & lt; DZ, fac DZ - {I/R} KZ. DZ : : DK. DY; & ſume DY verſus A.

6. Quum denuò cadit Z inter D, & K, fiat DZ + {I/R} KZ. DZ : :
DK. DY; ſumatúrque DY verſus A.

Corol. Ad in regram Sphæram diυerg.

1. Si AB + AC & gt; {2R/I} AC; fiat AB + AC - {2R/I} AC. AC : : BC. CY; & cape CY adverſus A.

2. Si AB + AC = {2R/I} AC; imago in infinitum abit.

3. Si AB + AC & lt; {2R/I} AC; fiat {2R/I} AC - AC - AB. AC : : BC. CY; capiatúrque CY verſus A.

_XIII._ Ad lentem concavc-concavam diverg.

Fig. 159.

_XIV._ Ad lentem convexo-convexam converg.

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