SAGR. I may then, it ſeems, for once prove a Maſter to you both.
And becauſe the proceeding by interrogatories doth in my opinion
much dilucidate things, beſides the pleaſure which it affords of
founding our companion, forcing from him that which he thought he
knew not, I will make uſe of that artifice. And firſt, I ſuppoſe that the
Ship, Gally, or other Veſſel, which we would diſcover, is a great way
off, that is, four, ſix, ten, or twenty ^{*} miles, for that to kenne thoſe
neer at hand there is no need of theſe Glaſſes: & conſequently, the
Teleſcope may at ſuch a diſtance of four or ſix miles conveniently
diſcover the whole Veſſel, & a muchgreater bulk. Now I demand
what for ſpecies, & how many for number are the motions that are
made upon the round top, depending on the fluctuation of the Ship.
And becauſe the proceeding by interrogatories doth in my opinion
much dilucidate things, beſides the pleaſure which it affords of
founding our companion, forcing from him that which he thought he
knew not, I will make uſe of that artifice. And firſt, I ſuppoſe that the
Ship, Gally, or other Veſſel, which we would diſcover, is a great way
off, that is, four, ſix, ten, or twenty ^{*} miles, for that to kenne thoſe
neer at hand there is no need of theſe Glaſſes: & conſequently, the
Teleſcope may at ſuch a diſtance of four or ſix miles conveniently
diſcover the whole Veſſel, & a muchgreater bulk. Now I demand
what for ſpecies, & how many for number are the motions that are
made upon the round top, depending on the fluctuation of the Ship.
SALV. We will ſuppoſe that the Ship goeth towards the Eaſt.
Firſt, in a calme Sea, it would have no other motion than
this of progreſſion, but adding the undulation of the Waves,
there ſhall reſult thence one, which alternately hoyſting and
ering the poop and prow, maketh the round top, to lean forwards
and backwards; other waves driving the veſſel ſidewayes, bow the
Maſt to the Starboard and Larboard; others, may bring the ſhip
ſomewhat abovt, and bear her away by the Miſne from Eaſt, one
while towards the ^{*} Northeaſt; another while toward the
eaſt; others bearing her up by the Carine may make her onely to
riſe, and fall; and in ſum, theſe motions are for ſpecies two, one
that changeth the direction of the Teleſcope angularly, the other
lineally, without changing angle, that is, alwayes keeping the
tube of the Inſtrument parallel to its ſelf.
Firſt, in a calme Sea, it would have no other motion than
this of progreſſion, but adding the undulation of the Waves,
there ſhall reſult thence one, which alternately hoyſting and
ering the poop and prow, maketh the round top, to lean forwards
and backwards; other waves driving the veſſel ſidewayes, bow the
Maſt to the Starboard and Larboard; others, may bring the ſhip
ſomewhat abovt, and bear her away by the Miſne from Eaſt, one
while towards the ^{*} Northeaſt; another while toward the
eaſt; others bearing her up by the Carine may make her onely to
riſe, and fall; and in ſum, theſe motions are for ſpecies two, one
that changeth the direction of the Teleſcope angularly, the other
lineally, without changing angle, that is, alwayes keeping the
tube of the Inſtrument parallel to its ſelf.
* Greco, which
the Latine
ſlator according to
his uſual
neſſe (to call it no
worſe) tranſlates
Corum Ventum,
the Northweſt
Wind, for Ventum
Libanotum.
the Latine
ſlator according to
his uſual
neſſe (to call it no
worſe) tranſlates
Corum Ventum,
the Northweſt
Wind, for Ventum
Libanotum.
SAGR. Tell me, in the next place, if we, having firſt directed
the Teleſcope yonder away towards the Tower of ^{*} Burano, ſix
miles from hence, do turn it angularly to the right hand, or to the
left, or elſe upwards or downwards, but a ^{*}ſtraws breadth, what
fect ſhall it have upon us touching the finding out of the ſaid tower?
the Teleſcope yonder away towards the Tower of ^{*} Burano, ſix
miles from hence, do turn it angularly to the right hand, or to the
left, or elſe upwards or downwards, but a ^{*}ſtraws breadth, what
fect ſhall it have upon us touching the finding out of the ſaid tower?
SALV. It would make us immediately loſe ſight of it, for ſuch
a declination, though ſmall here, may import there hundreds and
thouſands of yards.
a declination, though ſmall here, may import there hundreds and
thouſands of yards.
SAGR. But if without changing the angle, keeping the tube
alwayes parallel to it ſelf, we ſhould transfer it ten or twelve
yards farther off to the right or left hand, upwards or downwards,
what alteration would it make as to the Tower?
alwayes parallel to it ſelf, we ſhould transfer it ten or twelve
yards farther off to the right or left hand, upwards or downwards,
what alteration would it make as to the Tower?
SALV. The change would be abſolutely undiſcernable; for
that the ſpaces here and there being contained between parallel
rayes, the mutations made here and there, ought to be equal, and
becauſe the ſpace which the Inſtrument diſcovers yonder, is
ble of many of thoſe Towers; therefore we ſhall not loſe ſight of it.
that the ſpaces here and there being contained between parallel
rayes, the mutations made here and there, ought to be equal, and
becauſe the ſpace which the Inſtrument diſcovers yonder, is
ble of many of thoſe Towers; therefore we ſhall not loſe ſight of it.