Ibn-al-Haitam, al-Hasan Ibn-al-Hasan; Witelo; Risner, Friedrich, Opticae thesavrvs Alhazeni Arabis libri septem, nunc primùm editi. Eivsdem liber De Crepvscvlis & Nubium ascensionibus. Item Vitellonis Thuvringopoloni Libri X. Omnes instaurati, figuris illustrati & aucti, adiectis etiam in Alhazenum commentarijs, a Federico Risnero, 1572

Table of figures

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[201] k q p t ſ n g b o r f e u m z d h a
[202] t i n g y z x q m b c œ f h z r a d p e K o
[203] u r h d x b y m ſ o n f g i k q z t c c s a
[204] p b o n m d r h c t a K
[205] d g p i t k n u b e a o f q l h m r
[206] a h p u m z t x b n c q s d g ſ K f r
[207] d g p i t k n z u b e a ſ o q l h m r
[208] h n m ſ a s x t r c e d z b g o p q k
[209] u g z y x r s t
[Figure 210]
[Figure 211]
[212] a h e d c b k q l g f
[213] a d c g b e f
[214] k n m x b l p f s u z y t
[215] k n b l o q f g u z
[216] k n m b l d p o q f g u
[217] k b d o f u g z r e a
[218] k h b m z d e a t i g
[219] h m k o n q e f p g i
[220] a k h g p d b c l
[221] a p h f l g e o k a n m e z q b
[222] a f h p g o e k d m n c q z b
[223] a f h p l g o e k d b m c q z n
[224] a f l p g e o k d b n m c z
[225] h a b g e f d e z
[226] h a b e d c z
[227] e a b d f c
[228] a r c p e h b z b d
[229] a n r l c x m h e p z g b b f d o k
[230] a l g h e z d k b t
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          <p>
            <s xml:id="echoid-s17177" xml:space="preserve">
              <pb o="244" file="0250" n="250" rhead="ALHAZEN"/>
            diſtans eſt primæ lineæ ſignatæ in ſuperficie laminæ, cuius extremitas peruenit ad primũ ſignum,
              <lb/>
            ſignatum in circumferentia medij circuli, & tanget
              <lb/>
              <figure xlink:label="fig-0250-01" xlink:href="fig-0250-01a" number="214">
                <variables xml:id="echoid-variables201" xml:space="preserve">k n m x b l p
                  <gap/>
                f s u z y t</variables>
              </figure>
            etiam ſuperficiem aquæ:</s>
            <s xml:id="echoid-s17178" xml:space="preserve"> locus enim harum duarum
              <lb/>
            linearũ non differt in reſpectu ſuperficiei aquæ, quò
              <lb/>
            ad ſenſum.</s>
            <s xml:id="echoid-s17179" xml:space="preserve"> Et hæc linea continet cum linea exeunte
              <lb/>
            à centro medij circuli ad ſignum, quod eſt in circum
              <lb/>
            ferentia medij circuli, perpendiculari ſuper ſuperfi-
              <lb/>
            ciem aquæ, angulum rectum:</s>
            <s xml:id="echoid-s17180" xml:space="preserve"> & diameter medιj cir-
              <lb/>
            culi, quæ tranſit per cẽtra duorum foraminum, con-
              <lb/>
            tinet cum hac perpendiculari exeunte à centro me-
              <lb/>
            dij circuli ſuper ſuperficiem aquæ, angulum, cuius
              <lb/>
            quantitas erit 80 partium.</s>
            <s xml:id="echoid-s17181" xml:space="preserve"> Hunc enim angulũ chor-
              <lb/>
            dat arcus medij circuli, qui eſt inter ſecundũ & ter-
              <lb/>
            tium ſignum:</s>
            <s xml:id="echoid-s17182" xml:space="preserve"> arcus autem, qui eſt inter centrum fo-
              <lb/>
            raminis & primum ſignum, qui eſt 10 partium, chor-
              <lb/>
            dat angulum declinationis.</s>
            <s xml:id="echoid-s17183" xml:space="preserve"> Deinde oportet experi-
              <lb/>
            mentatorem conſiderare ſolẽ, & mutare inſtrumen-
              <lb/>
            tum, doneclux tranſeat per duo foramina:</s>
            <s xml:id="echoid-s17184" xml:space="preserve"> & tunc
              <lb/>
            aſpiciat lucem, quæ eſt in ora inſtrumenti, quæ eſt intra aquam, & ſignet ſuper centrũ lucis ſignum:</s>
            <s xml:id="echoid-s17185" xml:space="preserve">
              <lb/>
            hoc ergo ſignum erit in circumferentia medij circuli:</s>
            <s xml:id="echoid-s17186" xml:space="preserve"> deinde auferat inſtrumentum, & aſpicιat ter-
              <lb/>
            tium ſignum, quod eſt inter extremitatem medij circuli, & inter ſecundum ſignum, quod eſt extre-
              <lb/>
            mitas perpendicularis, exeuntis à cẽtro medιj circuli ſuper ſuperficiem aquæ.</s>
            <s xml:id="echoid-s17187" xml:space="preserve"> Ex hac ergo experi-
              <lb/>
            mentatione patebit, quòd angulus refractionis eſt ille, quem chordat arcus, qui eſt inter centrũ lu-
              <lb/>
            cis & tertium ſignum, quod eſt extremitas lineæ tranſeuntis per centra duorum foraminum, per
              <lb/>
            quam extendebatur lux:</s>
            <s xml:id="echoid-s17188" xml:space="preserve"> & ex numero partium huius arcus patebit quantitas anguli refractionis,
              <lb/>
            & quantitas proportionis anguli refractionis ad 80 partes, quæ eſt angulus, quẽ continet linea, per
              <lb/>
            quam extendebatur lux, cum perpendiculari exeunte à puncto refractionis ſuper ſuperficiẽ aquæ.</s>
            <s xml:id="echoid-s17189" xml:space="preserve">
              <lb/>
            Deinde oportet experimentatorem delere ſignum & lineam ſignatam in lamina, & diſtinguere in-
              <lb/>
            ter circumferentiam medij circuli ex parte centri foraminis, quod eſt in ora inſtrumenti arcum, cu-
              <lb/>
            ius quãtitas ſit 20 partium:</s>
            <s xml:id="echoid-s17190" xml:space="preserve"> & ſignet in extremitate eius ſignum, & extrahat ab hoc ſigno perpendi-
              <lb/>
            cularem ſuper ſuperficiem laminæ, & extrahat ab eιus extremitate lineam ad centrum laminæ:</s>
            <s xml:id="echoid-s17191" xml:space="preserve"> &
              <lb/>
            protrahamus illam in utramq;</s>
            <s xml:id="echoid-s17192" xml:space="preserve"> partem:</s>
            <s xml:id="echoid-s17193" xml:space="preserve"> & diuidamus arcum ſequente
              <gap/>
            illum (cuius quantitas 20)
              <lb/>
            in partes 90:</s>
            <s xml:id="echoid-s17194" xml:space="preserve"> & ſignemus in ipſo ſignum:</s>
            <s xml:id="echoid-s17195" xml:space="preserve"> & erit arcus, qui eſt inter ſignum ſecundum & extremita-
              <lb/>
            tem lineæ tranſeuntis per centra duorum foraminum, 70 partium:</s>
            <s xml:id="echoid-s17196" xml:space="preserve"> & ſignemus in extremitate hu-
              <lb/>
            ius lineæ ſignum.</s>
            <s xml:id="echoid-s17197" xml:space="preserve"> Dein de ponamus inſtrumentũ in uas, & reuoluamus illud, quouſq;</s>
            <s xml:id="echoid-s17198" xml:space="preserve"> linea ſignata
              <lb/>
            in lamina tangat ſuperficiem aquæ.</s>
            <s xml:id="echoid-s17199" xml:space="preserve"> Linea ergo, quæ exit à centro circuli medιj ad ſecundũ ſignum,
              <lb/>
            erit perpendicularis ſuper ſuperficiem aquæ, ut prædictum eſt:</s>
            <s xml:id="echoid-s17200" xml:space="preserve"> & linea, quæ tranſit per centra duo-
              <lb/>
            rum foraminum, continet cum hac perpendiculari angulum 70 partium.</s>
            <s xml:id="echoid-s17201" xml:space="preserve"> Deinde experimentator
              <lb/>
            conſideret ſolem, & moueat inſtrumentum, quouſq;</s>
            <s xml:id="echoid-s17202" xml:space="preserve"> lux tranſeat per duo foramina, & ſignet ſuper
              <lb/>
            centrum lucis ſignum, & auferat inſtrumentum, & aſpiciat ſigna, quæ ſunt in circumferentia medij
              <lb/>
            circuli:</s>
            <s xml:id="echoid-s17203" xml:space="preserve"> ex qua experimentatione habebit quãtiratem anguli refractionis, & proportionem eius ad
              <lb/>
            angulum, quem continet linea, per quam extenditur lux, cum perpendiculari exeunte à loco refra-
              <lb/>
            ctionis, qui eſt in hoc ſtatu 70 partiũ.</s>
            <s xml:id="echoid-s17204" xml:space="preserve"> Deinde experimentator auferat inſtrumentũ, & deleat ſigna,
              <lb/>
            & lineam, quæ eſt in lamina, & diuidat arcum ex parte foraminis, cuius quantitas ſit 30 partium, &
              <lb/>
            procedat, ut in primis ablationibus:</s>
            <s xml:id="echoid-s17205" xml:space="preserve"> & ſic habebit quãtitatem anguli refractionis & proportionem
              <lb/>
            eius ad angulum, quem continet linea, per quam extendebatur lux cum perpendiculari exeunte à
              <lb/>
            loco refractionis, qui eſt in hoc ſitu 60 partium.</s>
            <s xml:id="echoid-s17206" xml:space="preserve"> Deinde diuidamus arcum, cuius quantitas ſit 40
              <lb/>
            partium:</s>
            <s xml:id="echoid-s17207" xml:space="preserve"> deinde arcum, cuius quantitas ſit 50 partium:</s>
            <s xml:id="echoid-s17208" xml:space="preserve"> deinde 60:</s>
            <s xml:id="echoid-s17209" xml:space="preserve"> deinde 70:</s>
            <s xml:id="echoid-s17210" xml:space="preserve"> deinde 80:</s>
            <s xml:id="echoid-s17211" xml:space="preserve"> & conſide
              <lb/>
            ret unumquemq;</s>
            <s xml:id="echoid-s17212" xml:space="preserve"> iſtorum arcuum:</s>
            <s xml:id="echoid-s17213" xml:space="preserve"> & ſic habebit quãtitates angulorum refractionis, & angulorum
              <lb/>
            declinationis, quos chordant primi arcus diſtincti ex parte centri foraminis:</s>
            <s xml:id="echoid-s17214" xml:space="preserve"> & habebit proportio-
              <lb/>
            nes angulorum refractionis ad angulos, quos continent primæ lineæ, per quas extendebatur lux,
              <lb/>
            cum perpendiculari, quæ eſt in ſuperficie aquæ, qui creſcunt per decẽ.</s>
            <s xml:id="echoid-s17215" xml:space="preserve"> Et ſi experimentator uolue-
              <lb/>
            rit, ut anguli creſcant per quinq;</s>
            <s xml:id="echoid-s17216" xml:space="preserve">, bene poterit facere:</s>
            <s xml:id="echoid-s17217" xml:space="preserve"> & ſi uoluerit per minus, quàm per quinque,
              <lb/>
            bene poterit facere prædicto ordine.</s>
            <s xml:id="echoid-s17218" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div566" type="section" level="0" n="0">
          <head xml:id="echoid-head491" xml:space="preserve" style="it">11. Magnitudines angulorum refractionis ab aere uel aqua ad uitra planum uel conuexum,
            <lb/>
          & contrà, organo refractionis inuenire. 6 p 10.</head>
          <p>
            <s xml:id="echoid-s17219" xml:space="preserve">ET cum experimentator uoluerit experiri per uitrum:</s>
            <s xml:id="echoid-s17220" xml:space="preserve"> diuidat arcus, & ſignet prædicta ſigna,
              <lb/>
            & ſuperponat uitrum prædictum ſuperficiei laminæ, & ſuperponat differentiam eius cõmu-
              <lb/>
            nem lineæ ſignatæ in lamina, & ponat ſuperficiem uitri æqualem ex parte foraminum, & ap-
              <lb/>
            plicet uitrum bene, & ponat inſtrumentum in uaſe, & moueat ipſum, quouſq, lux tranſeat per duo
              <lb/>
            foramina, & ſignet ſuper centrum lucis ſignum, & auferat inſtrumentum, & intueatur arcus, & de-
              <lb/>
            inde deleat ſigna, & diuidat alios arcus, & ſignet alia ſigna, & inſpiciat arcus ꝓut aſpexit per aquã:</s>
            <s xml:id="echoid-s17221" xml:space="preserve">
              <lb/>
            & ſic habebit quantitates angulorum refractionis in tranſitu lucis de aere ad uitrum.</s>
            <s xml:id="echoid-s17222" xml:space="preserve"> Et ſi uoluerit
              <lb/>
            </s>
          </p>
        </div>
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