Omnes hos fafccs fimul excipit, effigiemque
Audiam , & finitam haud incerto limite cern it.
Hic
1
quoque jam fafces coeuntes denique in ip f i
Pup illa , flexu fele inclinare viciffim
Majori tanto deben t, quam, quem fine vitris
1 5 6 0
Conficerent r ad ii, quanto vicinior exeat-
Q u i lentes inter geminas focus anteriores
Commun is j a c e t , interrra vicinior, inquam*,
Quam primse cx fe rnxque ; igitur fic nolccre poflis,
Metirique augmen , dinienfus ut ante figura es.
1 5CT5
Cumque v o l e s 2 , oculis variis ut idoneus e x t e t ,
Hunc fecilTe tubum ; potes aut protrudere ternas
Introrfum lentes , aut contra extrudere cafdem ;
Falcium enim qui funt radii , tunc egredientur
Au t rarefeentes inter fe mutuipaulqm ,
1 570
Au t fe denfantes contra, ut diverfa tuentum
N 2
L u -
a p p lica tio
f a c ilis t c l c f c o p i i p r o
p resbita ,
te
r n y o p e , e d u c e n d o
tu b u lu m , q u i c o n t i n e a t l e n t e m
u l t i m a m , v e i t u b u m , q u i c o n
tin eat o m n i u m f y f t c m a , v e l i n
tru d e n d o , u t f o c u s r a d i o r u m p e r
tin e n tiu m
a d u n i c u m
q u o d v i s
o b j c & i pun < ftum j a c e a t a n t e , veL
p o f t f o c u m p o f t r c m x l e n t i s , a d e o
q u e ii a b h a c r e d d a n t u r n o n n i
h il c o n v e r g e n t e s , v e l d i v e r g e n
tes . P e r c d u c t i o n c m e j u s t u b u
li fic illu d e t i a m , u t i m a g o o b j e -
d i p in g a tu r fa tis d i f t i n d a a r a
diis ‘tra n fm iffis t r a n s t c l c l c o p i u m
in p la n o o b j c & o p e r p e n d i c u l a r i -
te r ipfi t u b o : n a m cdu<
5
t o i l l o
t u b u lo fieri p o t e f t , u t r a d ii p e r
tin e n te s ad q u o d v i s u n i c u j p o b j e -
<fti p u n ft u m c o e a n t in c a d i f t a n
tia , & i m a g i n e m i d c i r c o d i f t i i i -
f t a m ibi e x h i b e a n t . E a a p p a r e t
facis c l a r a , fi o b je d t u m . f it Itici -
d u m , uc fol ^ t e lo c u s n o n n i h i l
o h fc u r u s . E o p a < ftp f o l e n t o b f ? i -
v a ri te m a c u l x f o l is ,
Ite
C o la r e s
eclipfes
o r t x a b
i n t e r p o f i d o n Q
L u n x , ut
te
t r a n f it u s i n t e r i o m n i
p la n c ta ru m f u b f o l e e x h i b e r i e o
d em m o d o p o l i u n t ip fi v u l g o *
L I B E R O C T A V U S .
195
r A f f i r m a t i n h o c it id e m tcle -
f c o p i o h a b e r i a m p l i f ic a t io n c m d i-
v i f a
d i f t a n t i a
f o c a l i
o b jccftiv i ,
q u a m a p p e l l a t l e n t e m p r i m a m e x
t e r n a m , p e r d i f t a n t i a m f o c a l c m
p r i m x o c u l a r i s , q u a s
d ifta n tia s
e x p r i m i t , p e r d i f t a n t i a s fo c i c o m
m u n i s c a r u m l e n t i u m a b ip fis .
In q u o c u m q u e f y f t c m a t e o c u l a
r i u m ,
te
t e l c f c p p i o r u m g e n e r e
a m p l i f i c a t i o h a b e t u r j fi a n g u l u s ,
in q u o a d fe i n v i c e m i n c lin a n
tu r f a f c i c u l i p e r t i n e n t e s ad b in a
p u n d l a ob jc< fti q u x v i s , d iv id a tu r
p e r a n g u l u m , in q u o ad fc in
v i c e m in i p f o c e n t r o o b j c d l i v i in
c l i n a b a n t u r r a d i i m e d ii ad ip fo s
p e r t i n e n t e s . I b i ii a n g u l i f u n t ,
ut i l l x d i f t a n t i x in c o t e le fc o p io
c o m p o t i t o x q u e a c in fu jp crio rc
f i m p l i c i > n a m a n g u l u s f a f c ic u lo -
rurni
p r o d e u n t i u m e te r t ia o c u
lari a e q u a t u r a n g u l o p r o d e u n t i u m
c p r i m a o b
i p f a m a eq u a lita tem
( lif t a n t ia r u m f o c a l i u m . P r o o m n i
bus a l i i s c o n i b i n a t i o n i b u s f o r m u
la: g e n e r a l e s h a b e n t u r , q u x d e
te rm in e n t: c a m p u m fim u l c u m di*
f t i n d l i o n c ,
te
a m p l i f i c a t i o n e
2 H a b e t u r l i i c e t i a m id , q u o d
in f u p c r i o i i b u s h a b e r i d i x i m u s ,
