1ed; therefore tell me how he diſ-ingageth himſelf in the next place
from that particular of the Stars having conſtantly kept the ſame
diſtance from the fixed Stars circumjacent to it.
from that particular of the Stars having conſtantly kept the ſame
diſtance from the fixed Stars circumjacent to it.
SALV. He betakes himſelf, in like manner, to two threads, yet
more unable to uphold him than the former: one of which is
wiſe faſtened to refraction, but ſo much leſs firmly, in that he
ſaith, that refraction operating upon the new Star, and ſublimating
it higher than its true ſituation, maketh the ſeeming diſtances
tain to be diſtinguiſhed from the true, when compared to the
cumpoſed fixed Stars that environ it. Nor can I ſufficiently
mire how he can diſſemble his knowing how that the ſame
ction will work alike upon the new Star, as upon the antient one
its neighbour, elevating both equally, ſo as that ſuch a like
dent altereth not the ſpace betwixt them. His other ſubterfuge is
yet more unhappy, and carryeth with it much of ridiculous, it
ing founded upon the errour that may ariſe in the inſtrumen
peration it ſelf; whilſt that the Obſervator not being able to
conſtitute the centre of the eyes pupil in the centre of the
tant (an Inſtrument imployed in obſerving the diſtance between
two Stars) but holding it elevated above that centre, as much as
the ſaid pupil is diſtant from I know not what bone of the cheek,
againſt which the end of the Inſtrument reſteth, there is formed
in the eye an angle more acute than that which is made by the ſides
of the Inſtrument; which angle of rayes differeth alſo from it
ſelf, at ſuch time as a man looketh upon Stars, not much elevated
above the Horizon, and the ſame being afterwards placed at a
great height; that angle, ſaith he, is made different, while the
ſtrument goeth aſcending, the head ſtanding ſtill: but if in
ting the Inſtrument, the neck ſhould bend backwards, and the
head go riſing, together with the Inſtrument, the angle would then
continue the ſame. So that the Authours anſwer ſuppoſeth that
the Obſervators in uſing the Inſtrument have not raiſed the head,
as they ought to have done; a thing which hath nothing of
hood in it. But granting that ſo it had been, I leave you to judge
what difference can be between two acute angles of two
ral triangles, the ſides of one of which triangles are each four
[Italian] Braces [i.e. about three Engliſh yards] and thoſe of the
other, four braces within the quantity of the diameter of a Pea;
for the differences cannot be abſolutely greater between the length
of the two viſive rayes, whilſt the line is drawn perpendicularly
from the centre of the pupil, upon the plain of the Rule of the
Sextant (which line is no bigger than the breath of the thumb)
and the length of the ſame rayes, whilſt elevating the Sextant,
without raiſing the head together with it, that ſame line no longer
falleth perpendicularly upon the ſaid plane, but inclineth, making
more unable to uphold him than the former: one of which is
wiſe faſtened to refraction, but ſo much leſs firmly, in that he
ſaith, that refraction operating upon the new Star, and ſublimating
it higher than its true ſituation, maketh the ſeeming diſtances
tain to be diſtinguiſhed from the true, when compared to the
cumpoſed fixed Stars that environ it. Nor can I ſufficiently
mire how he can diſſemble his knowing how that the ſame
ction will work alike upon the new Star, as upon the antient one
its neighbour, elevating both equally, ſo as that ſuch a like
dent altereth not the ſpace betwixt them. His other ſubterfuge is
yet more unhappy, and carryeth with it much of ridiculous, it
ing founded upon the errour that may ariſe in the inſtrumen
peration it ſelf; whilſt that the Obſervator not being able to
conſtitute the centre of the eyes pupil in the centre of the
tant (an Inſtrument imployed in obſerving the diſtance between
two Stars) but holding it elevated above that centre, as much as
the ſaid pupil is diſtant from I know not what bone of the cheek,
againſt which the end of the Inſtrument reſteth, there is formed
in the eye an angle more acute than that which is made by the ſides
of the Inſtrument; which angle of rayes differeth alſo from it
ſelf, at ſuch time as a man looketh upon Stars, not much elevated
above the Horizon, and the ſame being afterwards placed at a
great height; that angle, ſaith he, is made different, while the
ſtrument goeth aſcending, the head ſtanding ſtill: but if in
ting the Inſtrument, the neck ſhould bend backwards, and the
head go riſing, together with the Inſtrument, the angle would then
continue the ſame. So that the Authours anſwer ſuppoſeth that
the Obſervators in uſing the Inſtrument have not raiſed the head,
as they ought to have done; a thing which hath nothing of
hood in it. But granting that ſo it had been, I leave you to judge
what difference can be between two acute angles of two
ral triangles, the ſides of one of which triangles are each four
[Italian] Braces [i.e. about three Engliſh yards] and thoſe of the
other, four braces within the quantity of the diameter of a Pea;
for the differences cannot be abſolutely greater between the length
of the two viſive rayes, whilſt the line is drawn perpendicularly
from the centre of the pupil, upon the plain of the Rule of the
Sextant (which line is no bigger than the breath of the thumb)
and the length of the ſame rayes, whilſt elevating the Sextant,
without raiſing the head together with it, that ſame line no longer
falleth perpendicularly upon the ſaid plane, but inclineth, making