1and indubitable fundamentals. And becauſe, as I ſay, I deſire de
monſtratively to aſſure you, and not with only probable diſcour
ſes to perſwade you; preſuppoſing, that you have ſo much know
ledge of the Mechanical Concluſions, by others heretofore funda
mentally handled, as ſufficeth for our purpoſe; it is requiſite, that
before we proceed any further, we conſider what effect that is which
opperates in the Fraction of a Beam of Wood, or other Solid, whoſe
parts are firmly connected; becauſe this is the firſt Notion, where
on the firſt and ſimple principle dependeth, which as familiarly
known, we may take for granted. For the clearer explanation
whereof; let us take the Cilinder, or Priſme, A. B. of Wood, or
other ſolid and coherent matter, faſtned above in A, and hanging
perpendicular; to which, at the other end B, let there hang the
Weight C: It is manifeſt, that how great ſoever the Tenacity and
coherence of the parts of the ſaid Solid to one another be, ſo it be
not infinite, it may be overcome by the
Force of the drawing Weight C: whoſe
Gravity I ſuppoſe may be encreaſed as much
52[Figure 52]
as we pleaſe; by the encreaſe whereof the
ſaid Solid in fine ſhall break, like as if it had
been a Cord. And, as in a Cord, we under
ſtand its reſiſtance to proceed from the mul
titude of the ſtrings or threads in the Hemp
that compoſe it, ſo in Wood we ſee its veins,
and grain diſtended lengthwaies, that render
it far more reſiſting againſt Fraction, then any
Rope would be, of the ſame thickneſſe: but
in a Cylinder of ſtone or Metal the Tenacity
of its parts, (which yet ſeemeth greater) de
pendeth on another kind of Cement,
than of ſtrings, or grains, and yet they alſo
being drawn with equivalent force, break.
monſtratively to aſſure you, and not with only probable diſcour
ſes to perſwade you; preſuppoſing, that you have ſo much know
ledge of the Mechanical Concluſions, by others heretofore funda
mentally handled, as ſufficeth for our purpoſe; it is requiſite, that
before we proceed any further, we conſider what effect that is which
opperates in the Fraction of a Beam of Wood, or other Solid, whoſe
parts are firmly connected; becauſe this is the firſt Notion, where
on the firſt and ſimple principle dependeth, which as familiarly
known, we may take for granted. For the clearer explanation
whereof; let us take the Cilinder, or Priſme, A. B. of Wood, or
other ſolid and coherent matter, faſtned above in A, and hanging
perpendicular; to which, at the other end B, let there hang the
Weight C: It is manifeſt, that how great ſoever the Tenacity and
coherence of the parts of the ſaid Solid to one another be, ſo it be
not infinite, it may be overcome by the
Force of the drawing Weight C: whoſe
Gravity I ſuppoſe may be encreaſed as much
52[Figure 52]as we pleaſe; by the encreaſe whereof the
ſaid Solid in fine ſhall break, like as if it had
been a Cord. And, as in a Cord, we under
ſtand its reſiſtance to proceed from the mul
titude of the ſtrings or threads in the Hemp
that compoſe it, ſo in Wood we ſee its veins,
and grain diſtended lengthwaies, that render
it far more reſiſting againſt Fraction, then any
Rope would be, of the ſame thickneſſe: but
in a Cylinder of ſtone or Metal the Tenacity
of its parts, (which yet ſeemeth greater) de
pendeth on another kind of Cement,
than of ſtrings, or grains, and yet they alſo
being drawn with equivalent force, break.
By Accademick
here, as in his
Dialogues of the
Syſteme, Galile
us meaneth him
ſelf.
here, as in his
Dialogues of the
Syſteme, Galile
us meaneth him
ſelf.
Ariſtotle the firſt
Obſerver of Me
chanical Concluſi
ons, but they nei
ther not the moſt
curious nor ſolidly
demonſtrated.
Obſerver of Me
chanical Concluſi
ons, but they nei
ther not the moſt
curious nor ſolidly
demonſtrated.
SIMP. If the thing ſucceed as you ſay, I underſtand well
enough, that the thread or grain of the Wood which is as long as
the ſaid Wood may make it ſtrong and able to Reſiſt a great vio
lence done to it to break it: But a Cord compoſed of ſtrings of
Hemp, no longer than two, or three foot a piece, how can it be ſo
ſtrong when it is ſpun out, it may be, to a hundred times that
length? Now I would farther underſtand your opinion concern
ing the Connection of the parts of Metals, Stones, and other mat
ters deprived of ſuch Ligatures, which nevertheleſſe, if I be not
deceived, are yet more tenacious.
enough, that the thread or grain of the Wood which is as long as
the ſaid Wood may make it ſtrong and able to Reſiſt a great vio
lence done to it to break it: But a Cord compoſed of ſtrings of
Hemp, no longer than two, or three foot a piece, how can it be ſo
ſtrong when it is ſpun out, it may be, to a hundred times that
length? Now I would farther underſtand your opinion concern
ing the Connection of the parts of Metals, Stones, and other mat
ters deprived of ſuch Ligatures, which nevertheleſſe, if I be not
deceived, are yet more tenacious.
SALV. We muſt be neceſſitated to digreſſe into new Specu
lations, and not much to our purpoſe, if we ſhould reſolve thoſe
difficulties you ſtart.
lations, and not much to our purpoſe, if we ſhould reſolve thoſe
difficulties you ſtart.