Archimedes, Natation of bodies, 1662

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1made of the Exceſs by which the Axis is greater than Seſquialter
of the Semi-parameter, hath to the Square made of the Axis, being
demitted into the Liquid, ſo as hath been ſaid, it ſhall ſtand erect,
or Perpendicular.
F
G
H
K
L
M
N
O
P
Q
R
COMMANDINE.
The particulars contained in this Tenth Propoſition, are divided by Archimedes
into five Parts and Concluſions, each of which he proveth by a diſtinct Demonſtration.
A
It ſhall ſometimes ſtand perpendicular.] This is the firſt Concluſion, the
Demonstration of which he hath ſubjoyned to the Propoſition.
B
And ſometimes ſo inclined, as that its Baſe touch the Surface
of the Liquid, in one Point only.] This is demonſtrated in the third Con­
cluſion.
Sometimes, ſo that its Baſe be moſt ſubmerged in the Liquid.]

This pertaineth unto the fourth Concluſion.
C
And, ſometimes, ſo as that it doth not in the leaſt touch the Sur­

face of the Liquid.] This it doth hold true two wayes, one of which is explained is
the ſecond, and the other in the fifth Concluſion.
D
According to the proportion, that it hath to the Liquid in Gra­

vity.
Every one of which Caſes ſhall be anon demonſtrated.]
In Tartaglia's Verſion it is rendered, to the confuſion of the ſence, Quam autem pro­
portionem habeant ad humidum in Gravitate fingula horum demonſtrabuntur.
E
It is manifeſt, therefore, that K C is greater than the Semi­

parameter] For, ſince B D hath to K C the ſame proportion, as fifteen to four, and
hath unto the Semi-parameter greater proportion; (a) the Semi-parameter ſhall be leſs

than K C.
F
(a) By 10. of the
fifth.
Let the Semi-parameter be equall to KR.] We have added theſe words,

which are not to be found in Tartaglia.
G
But S B is alſo Seſquialter of BR.] For, D B is ſuppoſed Seſquialter of

B K; and D S alſo is Seſquialter of K R: Wherefore as (b) the whole D B, is to the whole
B K, ſo is the part D S to the part K R. Therefore, the Remainder S B, is alſo to the

Remainder B R, as D B is to B K.
H
(b) By 19 of the
fifth.
And let them be like to the Portion A B L.] Apollonius thus defineth

like Portions of the Sections of a Cone, in Lib. 6. Conicornm, as Eutocius writeth ^{*};

ὄν οἱ̄ς ἀχ δεισω̄ν ὄν ἑχάσῳ ωαραλλήλων τη̄ <35>ὰσει, ἵσων τὸ πλη̄ο<34>, αἱ παράλληλος, καὶ ἁι <35>άσεις ωρὸς τάς αποτρμ
νομένας ἀπὸ διαμέτσων τω̄ς κορυφαῑς ἐν τοῑς ἀντοῑς λόγοις εἰσι, καὶ αἱ ἀποτεμνόμεναι ωρὸς τὰς ἀ τεμνομίνασ
that is, In both of which an equall number of Lines being drawn parallel to the
Baſe; the parallel and the Baſes have to the parts of the Diameters, cut off from
the Vertex, the ſameproportion: as alſo, the parts cut off, to the parts cut off.
Now the Lines parallel to the Baſes are drawn, as I ſuppoſe, by making a Rectilineall Figure (cal-

led) Signally inſcribed [χη̄μα γιωρίμως ἐγν̀<36>ρόμενον] in both portions, having an equall num­
ber of Sides in both.
Therefore, like Portions are cut off from like Sections of a Cone; and
their Diameters, whether they be perpendicular to their Baſes, or making equall Angles with their
Baſes, have the ſame proportion unto their Baſes.
K
* Upon prop. 3 lib. 2
Archim. Æqui­
pond.
Vide Archim, ante
prop. 2. lib. 2.
Æquipond.
L
Now the Section of the Cone A E I ſhall paſs thorow K.]
For, if it be poſſible, let it not paſs thorow K, but thorow ſome other Point of the Line D B, as
thorow V. Inregard, therefore, that in the Section of the Right-angled Cone A E I, whoſe
Diameter is E Z, A E is drawn and prolonged; and D B parallel unto the Diameter, cutteth
both A E and A I; A E in B, and A I in D; D B ſhall have to B V, the ſame proportion

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