Salusbury, Thomas
,
Mathematical collections and translations (Tome I)
,
1667
Text
Text Image
Image
XML
Thumbnail overview
Document information
None
Concordance
Figures
Thumbnails
page
|<
<
of 701
>
>|
<
archimedes
>
<
text
>
<
body
>
<
chap
>
<
pb
xlink:href
="
040/01/030.jpg
"
pagenum
="
14
"/>
<
p
type
="
main
">
<
s
>SAGR. </
s
>
<
s
>I do not very well underſtand the queſtion.</
s
>
</
p
>
<
p
type
="
main
">
<
s
>SALV. </
s
>
<
s
>I will expreſs it better by drawing a Figure: therefore
<
lb
/>
I will ſuppoſe the line A B [in
<
emph
type
="
italics
"/>
Fig.
<
emph.end
type
="
italics
"/>
3.] parallel to the Horizon,
<
lb
/>
and upon the point B, I will erect a perpendicular B C; and after
<
lb
/>
that I adde this ſlaunt line C A. </
s
>
<
s
>Underſtanding now the line C
<
lb
/>
A to be an inclining plain exquiſitely poliſhed, and hard, upon
<
lb
/>
which deſcendeth a ball perfectly round and of very hard matter,
<
lb
/>
and ſuch another I ſuppoſe freely to deſcend by the perpendicular
<
lb
/>
C B: will you now confeſs that the
<
emph
type
="
italics
"/>
impetus
<
emph.end
type
="
italics
"/>
of that which
<
lb
/>
ſcends by the plain C A, being arrived to the point A, may be
<
lb
/>
equal to the
<
emph
type
="
italics
"/>
impetus
<
emph.end
type
="
italics
"/>
acquired by the other in the point B, after
<
lb
/>
the deſcent by the perpendicular C
<
lb
/>
<
arrow.to.target
n
="
marg44
"/>
</
s
>
</
p
>
<
p
type
="
margin
">
<
s
>
<
margin.target
id
="
marg44
"/>
<
emph
type
="
italics
"/>
The impetuoſity of
<
lb
/>
moveables equally
<
lb
/>
approaching to the
<
lb
/>
centre, are equal.
<
emph.end
type
="
italics
"/>
</
s
>
</
p
>
<
p
type
="
main
">
<
s
>SAGR. </
s
>
<
s
>I reſolutely believe ſo: for in effect they have both the
<
lb
/>
ſame proximity to the centre, and by that, which I have already
<
lb
/>
granted, their impetuoſities would be equally ſufficient to re-carry
<
lb
/>
them to the ſame height.</
s
>
</
p
>
<
p
type
="
main
">
<
s
>SALV. </
s
>
<
s
>Tell me now what you believe the ſame ball would do
<
lb
/>
put upon the Horizontal plane A B?</
s
>
</
p
>
<
p
type
="
main
">
<
s
>
<
arrow.to.target
n
="
marg45
"/>
</
s
>
</
p
>
<
p
type
="
margin
">
<
s
>
<
margin.target
id
="
marg45
"/>
<
emph
type
="
italics
"/>
Vpon an
<
lb
/>
tall plane the
<
lb
/>
able lieth ſtill.
<
emph.end
type
="
italics
"/>
</
s
>
</
p
>
<
p
type
="
main
">
<
s
>SAGR. </
s
>
<
s
>It would lie ſtill, the ſaid plane having no declination.</
s
>
</
p
>
<
p
type
="
main
">
<
s
>SALV. </
s
>
<
s
>But on the inclining plane C A it would deſcend, but
<
lb
/>
with a gentler motion than by the perpendicular C B?</
s
>
</
p
>
<
p
type
="
main
">
<
s
>SAGR. </
s
>
<
s
>I may confidently anſwer in the affirmative, it
<
lb
/>
ing to me neceſſary that the motion by the perpendicular C B
<
lb
/>
ſhould be more ſwift, than by the inclining plane C A; yet
<
lb
/>
vertheleſs, iſ this be, how can the Cadent by the inclination
<
lb
/>
rived to the point A, have as much
<
emph
type
="
italics
"/>
impetus,
<
emph.end
type
="
italics
"/>
that is, the ſame
<
lb
/>
gree of velocity, that the Cadent by the perpendicular ſhall have
<
lb
/>
in the point B? theſe two Propoſitions ſeem contradictory.</
s
>
</
p
>
<
p
type
="
main
">
<
s
>
<
arrow.to.target
n
="
marg46
"/>
</
s
>
</
p
>
<
p
type
="
margin
">
<
s
>
<
margin.target
id
="
marg46
"/>
<
emph
type
="
italics
"/>
The veloeity by the
<
lb
/>
inclining plane
<
lb
/>
qual to the
<
lb
/>
ty by the
<
lb
/>
oular, and the
<
lb
/>
tion by the
<
lb
/>
dicular ſwifter
<
lb
/>
than by the
<
lb
/>
nation.
<
emph.end
type
="
italics
"/>
</
s
>
</
p
>
<
p
type
="
main
">
<
s
>SALV. </
s
>
<
s
>Then you would think it much more falſe, ſhould I
<
lb
/>
ſay, that the velocity of the Cadents by the perpendicular, and
<
lb
/>
inclination, are abſolutely equal: and yet this is a Propoſition
<
lb
/>
moſt true, as is alſo this that the Cadent moveth more ſwiftly by
<
lb
/>
the perpendicular, than by the inclination.</
s
>
</
p
>
<
p
type
="
main
">
<
s
>SAGR. </
s
>
<
s
>Theſe Propoſitions to my ears ſound very harſh: and
<
lb
/>
I believe to yours
<
emph
type
="
italics
"/>
Simplicius
<
emph.end
type
="
italics
"/>
?</
s
>
</
p
>
<
p
type
="
main
">
<
s
>SIMPL. </
s
>
<
s
>I have the ſame ſenſe of them.</
s
>
</
p
>
<
p
type
="
main
">
<
s
>SALV. </
s
>
<
s
>I conceit you jeſt with me, pretending not to
<
lb
/>
hend what you know better than my ſelf: therefore tell me
<
emph
type
="
italics
"/>
<
lb
/>
plicius,
<
emph.end
type
="
italics
"/>
when you imagine a moveable more ſwift than
<
lb
/>
ther, what conceit do you fancy in your mind?</
s
>
</
p
>
<
p
type
="
main
">
<
s
>SIMPL. </
s
>
<
s
>I fancie one to paſs in the ſame time a greater ſpace
<
lb
/>
than the other, or to move equal ſpaces, but in leſſer time.</
s
>
</
p
>
<
p
type
="
main
">
<
s
>SALV. </
s
>
<
s
>Very well: and for moveables equally ſwift, what's
<
lb
/>
your conceit of them?</
s
>
</
p
>
<
p
type
="
main
">
<
s
>SIMPL. </
s
>
<
s
>I fancie that they paſs equal ſpaces in equal times.</
s
>
</
p
>
</
chap
>
</
body
>
</
text
>
</
archimedes
>