DOI Page / Citation link:
https://doi.org/10.11588/diglit.68888#0221
todriness and moisture, so that’withone breathing upon it, I have ihade
it untwist a whole bout, and the Index or Hand has shew’d or pointed to
various divisions on the upper Face or Ring of the Instrument, according
as it was carried neerer and neerer to the fire, or -as the heat of the Sun
increased upon it.
Other trials I have made with Gut-strings,blit find them nothing neer
so sensible, though they also may be so contriv’d as to exhibit the
changes of the Air, as to driness and moisture, both by their stretching
and(hrinking in length, and allo by their wreathing and unwrcathing
themfelves 5 but thefe are nothing neer so exacft or so tender5for their va-
rying property will in a little time change very much. But there are se-
veral other Vegetable substances that are much more sensible then even
this Beard of a wilde Oat--, Rich I have found the Beard ofthe seed of
Musk-grass, or Geranium mofchatum, and those of other kinds of Cranes-
bit feeds, and the like. But always the (mailer the wreathing substance
be, the more sensible is it of the mutations of the Air, a conjecture at
thereason of which I shall by and by add.
The lower end of this wreath’d Cylinder being stuck upright in a little
soft Wax, so that the bended part or Index of it lay horizontal., I have
observ’d it always with moislure to unwreath it self from the East (For
instance) by the South to the West,and so by the North to the East again,
moving with the Sun (as we commonly say) and with heat and drouth
tore-twist, and wreath it self the contrary way, namely, from the East,
(for instance) by the North to the West, and sb onwards.
The cause of all which rhanomena^ feems to be the differing texture
of the parts ofthese bodies, each of them (cspecially the Beard of a wilde
Oat., and of Moskrgrass feed J seeming to have two kind of substances,one
that is very porousdoose,and spongie, into which the watry steams ofthe
Air may be very easily forced^which will be thereby (well'd and extend-
ed in its dimensions, just as we may obferve all kind of Vegetable sub-
stance upon steeping in water to swell and grow bigger and longer. And a
fecond that is more hard and clofe,into which the water can very little,or
not at all penetrate, this therefore retaining always very neer the same
dimensions, and the other stretching and shrinking, according as there
is more or less moisture or water in its pores, by reason of the make and
shape of the parts, the whole body must necessarily unwreath and
wreath it self.
And upon this Principle, it is very easie to make feveral sorts of con-
trivances that should thus wreath and unwreath themselves, either by
heat and cold, or by driness and moisture, or by any greater or less force,
from whatever caufe it proceed, whether from gravity or weight, or
from wind which is motion of the Air, or from feme springing body,
or the like.
This, had I time, I should enlarge much more upon 5 for it feems to me
to be the very first footstep of Senfation., and Animate motion, the most
plain,simple,and obvious contrivance that Nature has made use of to pro-
duce a motion, next to that of Rarefaction and Condensation by heat
and
it untwist a whole bout, and the Index or Hand has shew’d or pointed to
various divisions on the upper Face or Ring of the Instrument, according
as it was carried neerer and neerer to the fire, or -as the heat of the Sun
increased upon it.
Other trials I have made with Gut-strings,blit find them nothing neer
so sensible, though they also may be so contriv’d as to exhibit the
changes of the Air, as to driness and moisture, both by their stretching
and(hrinking in length, and allo by their wreathing and unwrcathing
themfelves 5 but thefe are nothing neer so exacft or so tender5for their va-
rying property will in a little time change very much. But there are se-
veral other Vegetable substances that are much more sensible then even
this Beard of a wilde Oat--, Rich I have found the Beard ofthe seed of
Musk-grass, or Geranium mofchatum, and those of other kinds of Cranes-
bit feeds, and the like. But always the (mailer the wreathing substance
be, the more sensible is it of the mutations of the Air, a conjecture at
thereason of which I shall by and by add.
The lower end of this wreath’d Cylinder being stuck upright in a little
soft Wax, so that the bended part or Index of it lay horizontal., I have
observ’d it always with moislure to unwreath it self from the East (For
instance) by the South to the West,and so by the North to the East again,
moving with the Sun (as we commonly say) and with heat and drouth
tore-twist, and wreath it self the contrary way, namely, from the East,
(for instance) by the North to the West, and sb onwards.
The cause of all which rhanomena^ feems to be the differing texture
of the parts ofthese bodies, each of them (cspecially the Beard of a wilde
Oat., and of Moskrgrass feed J seeming to have two kind of substances,one
that is very porousdoose,and spongie, into which the watry steams ofthe
Air may be very easily forced^which will be thereby (well'd and extend-
ed in its dimensions, just as we may obferve all kind of Vegetable sub-
stance upon steeping in water to swell and grow bigger and longer. And a
fecond that is more hard and clofe,into which the water can very little,or
not at all penetrate, this therefore retaining always very neer the same
dimensions, and the other stretching and shrinking, according as there
is more or less moisture or water in its pores, by reason of the make and
shape of the parts, the whole body must necessarily unwreath and
wreath it self.
And upon this Principle, it is very easie to make feveral sorts of con-
trivances that should thus wreath and unwreath themselves, either by
heat and cold, or by driness and moisture, or by any greater or less force,
from whatever caufe it proceed, whether from gravity or weight, or
from wind which is motion of the Air, or from feme springing body,
or the like.
This, had I time, I should enlarge much more upon 5 for it feems to me
to be the very first footstep of Senfation., and Animate motion, the most
plain,simple,and obvious contrivance that Nature has made use of to pro-
duce a motion, next to that of Rarefaction and Condensation by heat
and