Salusbury, Thomas, Mathematical collections and translations (Tome I), 1667

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            <p type="main">
              <s>
                <pb xlink:href="040/01/078.jpg" pagenum="62"/>
              times bigger than the naked and real body: and a like or greater
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              augmentation doth the image of the Sun make, which you ſee in
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              that glaſs. </s>
              <s>I ſay greater, for that it is more lively than the ſtar,
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              as is manifeſt from our being able to behold the ſtar with much
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              leſs offence, than this reflection of the glaſs. </s>
              <s>The reverberation
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              therefore which is to diſpere it ſelf all over this wall, cometh from
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              a ſmall part of that glaſs, and that which even now came from
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              the whole flat glaſs diſperſed and reſtrain'd it ſelf to a very ſmall
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              part of the ſaid wall. </s>
              <s>What wonder is it then, that the firſt
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              flection very lively illuminates, and that this other is almoſt
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              perceptible?</s>
            </p>
            <p type="margin">
              <s>
                <margin.target id="marg168"/>
                <emph type="italics"/>
              The ſmall body of
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              the ſtars fringed
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              round about with
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              rays, appeareth
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              ry much biggerthan
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              plain and naked,
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              and in its native
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              clarity.
                <emph.end type="italics"/>
              </s>
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            <p type="main">
              <s>SIMPL. </s>
              <s>I find my ſelf more perplexed than ever, and there
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              preſents it ſelf unto me the other difficulty, how it can be that
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              that wall, being of a matter ſo obſcure, and of a ſuperficies ſo
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              poliſh'd, ſhould be able to dart from it greater light, than a glaſs
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              very ſmooth and polite.</s>
            </p>
            <p type="main">
              <s>SALV. </s>
              <s>Greater light it is not, but more univerſal; for as to
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              the degree of brightneſs, you ſee that the reflection of that ſmall
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              flat glaſs, where it beamed forth yonder under the ſhadow of the
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              penthouſe, illuminateth very much; and the reſt of the wall which
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              receiveth the reflection of the wall on which the glaſs is placed,
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              is not in any great meaſure illuminated, as was the ſmall part on
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              which the reflection of the glaſs fell. </s>
              <s>And if you would
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              ſtand the whole of this buſineſs, you muſt conſider that the
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                <arrow.to.target n="marg169"/>
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              ficies of that wall's being rough, is the ſame as if it were
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              ſed of innumerable ſmall ſuperficies, diſpoſed according to
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              numerable diverſities of inclinations: amongſt which it
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              rily happens, that there are many diſpoſed to ſend forth their
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              reflex rays from them into ſuch a place, many others into another:
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              and in ſum, there is not any place to which there comes not very
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              many rays, reflected from very many ſmall ſuperficies, diſperſed
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              throughout the whole ſuperficies of the rugged body, upon which
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              the rays of the Sun fall. </s>
              <s>From which it neceſſarily
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              eth, That upon any, whatſoever, part of any ſuperficies,
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              oppoſed to that which receiveth the primary incident rays,
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              there is produced reflex rays, and conſequently
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              nation. </s>
              <s>There doth alſo follow thereupon, That the ſame
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              body upon which the illuminating rays fall, beheld from
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              whatſoever place, appeareth all illuminated and ſhining: and
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              therefore the Moon, as being of a ſuperficies rugged and
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                <arrow.to.target n="marg170"/>
                <lb/>
              not ſmooth, beameth forth the light of the Sun on every
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              ſide, and to all beholders appeareth equally lucid. </s>
              <s>But if
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              the ſurface of it, being ſpherical, were alſo ſmooth as a glaſs, it
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              would become wholly inviſible; foraſmuch as that ſmall part,
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              from which the image of the Sun ſhould be reflected unto the eye </s>
            </p>
          </chap>
        </body>
      </text>
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