Barrow, Isaac, Lectiones opticae & geometricae : in quibus phaenomenon opticorum genuinae rationes investigantur, ac exponuntur: et generalia curvarum linearum symptomata declarantur

Table of contents

< >
[41.] Lect. XI.
[42.] APPENDICUL A.
[43.] Lect. XII.
[44.] APPENDICULA 1.
[45.] Præparatio Communis.
[46.] APPENDICULA 2.
[47.] Conicorum Superſicies dimetiendi Metbodus.
[48.] Exemplum.
[49.] Prop. 1.
[50.] Prop. 2.
[51.] Prop. 3.
[52.] Prop. 4.
[53.] APPENDICULA 3.
[54.] Problema I.
[55.] Exemp. I.
[56.] Exemp. II.
[57.] Probl. II.
[58.] Exemp. I.
[59.] _Exemp_. II.
[60.] _Probl_. III.
[61.] _Probl_. IV.
[62.] _Probl_. V.
[63.] _Probl_. VI.
[64.] _Probl_. VII
[65.] _Probl_. VIII.
[66.] _Probl_. IX.
[67.] _Probl_. X.
[68.] _Corol. Theor_. I.
[69.] _Theor_. II.
[70.] _Theor_. III.
< >
page |< < (26) of 393 > >|
4426 GP _a_, HP δ ità diſponantur, ut latera PG, PH ſibi congruant (un-
de major angulus GP _a_ minorem HP δ comprehendet) tum centro P
per δ deſcribatur circulus E δ F ipſas PG, P _a_ ſecans punctis F, E;
item
connexâ EH, centro H per δ tranſeat circulus HMN ipſas HP, HE
ſecans punctis N, M;
denuò connexa E δ cum PG conveniat in L.
Eſtque jam ang. _a_ P δ. ang. δ PH: : ſector EP δ. ſector δ PF & gt;
triang.
EP δ. triang. δ PL: : Eδ. δ L : : triang. EH δ. δ HL & gt;
ſector MH δ.
ſector δ HN : : ang. EH δ. ang. δ HP. eſt igi-
tur ang.
_a_ P δ. ang. δ PH & gt; ang. EH δ. ang. δ HP. ergóque
compoſitè ang.
_a_ PG. ang. δ PH & gt; ang. EHP. ang. δ HP. per-
mutandóque ang.
_a_ PG. ang. EHP & gt; ang. δ PH. ang. δ HP. eſt
autem HP.
PE : : HP. P δ : : I. R : : GP. P _a_. adeoque EH ad
_a_ G parallela;
vel ang. EHP = ang. _a_ GP. ergò erit ang. _a_ PG.
ang.
_a_ GP & gt; ang. δ PH. ang. δ HP. hoc eſt ang. _a_ BG, _a_ BP
&
gt; ang. δ BH. ang. δ BP. vel componendo ang. GBP. ang. _a_ BP
&
gt; ang HBP. ang. δ BP. Quod erat demonſtrandum.
_Corol_. 1. Ang. _a_ BG. ang. _a_ BP &gt; ang. δ BH. ang. δ BP.
2. Ang. _a_ BG. ang. PBG &gt; ang. δ BH. PBH.
Opportunum eſt hoc Theorema conciliandis cum experientia pro-
poſitis refractionum legibus.
Ut demirari ſubeat nuperrimum Opticæ
ſcriptorem, virum alioqui diffuſè doctum, hujuſmodi ratiocinio leges
iſtas impugnàſſe:
“In majoribus tamen angulis inclinationis (Ipſiſ-
"ſima ſunt ejus verba) falſum eſſe conſtat (principium nempe no-
"ſtrum;)
in his enim angulus refractionis major eſt ſubtriplo an-
"guli inclinationis;
quod mihi aliiſque ex luculentis experimentis
"compertum eſt.
Hæc, inquam, ille ταντοεπ@. Quaſi verò dixiſſet;
numeri 6 & 4 ſimul accepti non conficiunt 10, quia numerum effici-
unt majorem quam 8.
planè ſimilis eſt diſcurſus; non ovum ovo ſi-
milius.
Nam in refractionibus ex. gr. ad vitrum factis ſi ponatur ad
quamvis inclinationem (puta graduum 15.)
quòd ſit angulus refra-
ctionis ſubtriplus anguli inclinationis (quem ille vocat, incidentiæ nos
angulum appellare ſolemus) neceſſariò, ſicuti modò demonſtratum
eſt, è principio noſtro conſequetur, quòd ad aliam quamcunque ma-
jorem inclinationem refractionis angulus major erit ſubtriplo anguli
inclinationis;
nominatim acceptâ graduum 30 inclinatione juxta di-
ctum principium inſtitutus calculus angulum præbebit reſractum
19.
24'; angulúmque proinde refractionis 10. 36', qui 30 graduum
trientem exuperat.
Quare cùm Clariſſimus vir Hypotheſin hanc

Text layer

  • Dictionary

Text normalization

  • Original

Search


  • Exact
  • All forms
  • Fulltext index
  • Morphological index