There is a certain Down of a Plant, brought from the _East-Indies_, call’d
commonly, though very improperly, _Cow-itch_, the reason of which mistake
is manifest enough from the description of it, which Mr. _Parkinson_ sets
down in his _Herbal_, Tribe XI. Chap. 2. _Phasiolus siliqua hirsuta; The
hairy Kidney-bean, called in _Zurratte_ where it grows, Couhage: We have
had_ (says he) _another of this kind brought us out of the _East-Indies_,
which being planted was in shew like the former, but came not to
perfection, the unkindly season not suffering it to shew the flower; but of
the Cods that were brought, some were smaller, shorter, and rounder then
the Garden kind; others much longer, and many growing together, as it were
in clusters, and cover’d all over with a brown short hairiness, so fine,
that if any of it be rubb’d, or fall on the back of ones hand, or other
tender parts of the skin, it will cause a kind of itching, but not strong,
nor long induring, but passing quickly away, without either danger or harm;
the Beans were smaller then ordinary, and of a black shining colour._
Having one of these Cods given me by a Sea-Captain, who had frequented
those parts, I found it to be a small Cod, about three Inches long, much
like a short Cod of _French Beans_, which had six Beans in it, the whole
surface of it was cover’d over with a very thick and shining brown Down or
Hair, which was very fine, and for its bigness stiff; taking some of this
Down, and rubbing it on the back of my hand, I found very little or no
trouble, only I was sensible that several of these little downy parts with
rubbing did penetrate, and were sunk, or stuck pretty deep into my skin.
After I had thus rubb’d it for a pretty while, I felt very little or no
pain, in so much that I doubted, whether it were the true Couhage; but
whil’st I was considering; I found the Down begin to make my hand itch, and
in some places to smart again, much like the stinging of a Flea or Gnat,
and this continued a pretty while, so that by degrees I found my skin to be
swell’d with little red pustules, and to look as if it had been itchie. But
suffering it without rubbing or scratching, the itching tickling pain
quickly grew languid, and within an hour I felt nothing at all, and the
little _protuberancies_ were vanish’d.
The cause of which odd _Phænomenon_, I suppose to be much the same with
that of the stinging of a Nettle, for by the _Microscope_, I discover’d
this Down to consist of a multitude of small and slender conical bodies,
much resembling Needles or Bodkins, such as are represented by AB. CD. EF.
of the first Figure of the XVI. _Scheme_; that their ends AAA, were very
sharp, and the substance of them stiff and hard, much like the substance of
several kinds of Thorns and crooks growing on Trees. And though they
appear’d very cleer and transparent, yet I could not perceive whether they
were hollow or not, but to me they appear’d like solid transparent bodies,
without any cavity in them; whether, though they might not be a kind of
Cane, fill’d with some transparent liquor which was hardned (because the
Cod which I had was very dry) I was not able to examine.
Now, being such stiff, sharp bodies, it is easie to conceive, how with
rubbing they might easily be thrust into the tender parts of the skin, and
there, by reason of their exceeding fineness and driness, not create any
considerable trouble or pain, till by remaining in those places moistned
with the humours of the body, some caustick part sticking on them, or
residing within them might be dissolv’d and mix’d with the ambient juices
of that place, and thereby those _fibres_ and tender parts adjoyning become
affected, and as it were corroded by it; whence, while that action lasts,
the pains created are pretty sharp and pungent, though small, which is the
essential property of an itching one.
That the pain also caused by the stinging of a Flea, a Gnat, a Flie, a
Wasp, and the like, proceeds much from the very same cause, I elsewhere in
their proper places endeavour to manifest. The stinging also of shred
Hors-hair, which in meriment is often strew’d between the sheets of a Bed,
seems to proceed from the same cause.
* * * * *
Observ. XXVII. _Of the _Beard_ of a wilde _Oat_, and the use that may be
made of it for exhibiting always to the Eye the temperature of the Air, as
to driness and moisture._
This Beard of a wild _Oat_, is a body of a very curious structure, though
to the naked Eye it appears very slight, and inconsiderable, it being only
a small black or brown Beard or Bristle, which grows out of the side of the
inner Husk that covers the Grain of a wild _Oat_; the whole length of it,
when put in Water, so that it may extend it self to its full length, is not
above an Inch and a half, and for the most part somewhat shorter, but when
the Grain is ripe, and very dry, which is usually in the Moneths of _July_,
and _August_, this Beard is bent somewhat below the middle, namely, about
⅖ from the bottom of it, almost to a right Angle, and the under part of
it is wreath’d lik a With; the substance of it is very brittle when dry,
and it will very easily be broken from the husk on which it grows.
If you take one of these Grains, and wet the Beard in Water, you will
presently see the small bended top to turn and move round, as if it were
sensible; and by degrees, if it be continued wet enough, the joint or knee
will streighten it self; and if it be suffer’d to dry again, it will by
degrees move round another way, and at length bend again into its former
posture.
If it be view’d with an ordinary single _Microscope_, it will appear like a
small wreath’d Sprig, with two clefts; and if wet as before, and then
look’d on with this _Microscope_, it will appear to unwreath it self, and
by degrees, to streighten its knee, and the two clefts will become
streight, and almost on opposite sides of the small cylindrical body.
If it be continued to be look’d on a little longer with a _Microscope_, it
will within a little while begin to wreath it self again, and soon after
return to its former posture, bending it self again neer the middle, into a
kind of knee or angle.
Several of those bodies I examin’d with larger _Microscopes_, and there
found them much of the make of those two long wreath’d cylinders delineated
in the second Figure of the 15. _Scheme_, which two cylinders represent the
wreathed part broken into two pieces, whereof the end AB is to be suppos’d
to have join’d to the end CD, so that EACF does represent the whole
wreath’d part of the Beard, and EG a small piece of the upper part of the
Beard which is beyond the knee, which as I had not room to insert, so was
it not very considerable, either for its form, or any known property; but
the under or wreathed part is notable for both: As to its form, it
appear’d, if it were look’d on side-ways, almost like a Willow, or a small
tapering rod of _Hazel_, the lower or bigger half of which onely, is
twisted round several times, in some three, in others more, in others less,
according to the bigness and maturity of the Grain on which it grew, and
according to the driness and moisture of the ambient Air, as I shall shew
more at large by and by.
The whole outward Superficies of this Cylindrical body is curiously adorned
or fluted with little channels, and interjacent ridges, or little
_protuberances_ between them, which run the whole length of the Beard, and
are streight where the Beard is not twisted, and wreath’d where it is, just
after the same manner: each of those sides is beset pretty thick with small
Bristes or Thorns, somewhat in form resembling that of _Porcupines_ Quills,
such as _aaaaa_ in the Figure; all whose points are directed like so many
Turn-pikes towards the small end or top of the Beard, which is the reason,
why, if you endeavour to draw the Beard between your fingers the contrary
way, you will find it to stick, and grate, as it were, against the skin.
The proportion of these small conical bodies _aaaaa_ to that whereon they
grow, the Figure will sufficiently shew, as also their manner of growing,
their thickness, and nearness to each other, as, that towards the root or
bottom of the Beard, they are more thin, and much shorter, insomuch that
there is usually left between the top of the one, and the bottom of that
next above it, more then the length of one of them, and that towards the
top of the Beard they grow more thick and close (though there be fewer
ridges) so that the root, and almost half the upper are hid by the tops of
those next below them.
I could not perceive any _transverse_ pores, unless the whole wreath’d part
were separated and cleft, in those little channels, by the wreathing into
so many little strings as there were ridges, which was very difficult to
determine; but there were in the wreathed part two very conspicuous
channels or clefts, which were continued from the bottom F to the elbow
EH or all along the part which was wreath’d, which seem’d to divide the
wreath’d Cylinder into two parts, a bigger and a less; the bigger was that
which was at the _convex_ side of the knee, namely, on the side A, and was
wreath’d by OOOOO; this, as it seem’d the broader, so did it also the
longer, the other PPPPP, which was usually purs’d or wrinckled in the
bending of the knee, as about E, seem’d both the shorter and narrower, so
that at first I thought the wreathing and unwreathing of the Beard might
have been caus’d by the shrinking or swelling of that part; but upon
further examination, I found that the clefts, KK, LL, were stuft up with a
kind of Spongie substance, which, for the most part, was very conspicuous
neer the knee, as in the cleft KK, when the Beard was dry; upon the
discovery of which, I began to think, that it was upon the swelling of this
porous pith upon the access of moisture or water that the Beard, being made
longer in the midst, was streightned, and by the shrinking or subsiding of
the parts of that Spongie substance together, when the water or moisture
was exhal’d or dried, the pith or middle parts growing shorter, the whole
became twisted.
But this I cannot be positive in, for upon cutting the wreath’d part in
many places transversly, I was not so well satisfy’d with the shape and
manner of the pores of the pith; for looking on these transverse Sections
with a very good _Microscope_, I found that the ends of those transverse
Sections appear’d much of the manner of the third Figure of the 15.
_scheme_ ABCFE, and the middle of pith CC, seem’d very full of pores
indeed, but all of them seem’d to run the long-ways.
This Figure plainly enough shews in what manner those clefts, K and L
divided the wreath’d Cylinder into two unequal parts, and also of what kind
of substance the whole body consists; for by cutting the same Beard in many
places, with transverse Sections, I found much the same appearance with
this express’d; so that those pores seem to run, as in most other such Cany
bodies, the whole length of it.
The clefts of this body KK, and LL, seem’d (as is also express’d in the
Figure) to wind very oddly in the inner part of the wreath, and in some
parts of them, they seem’d stuffed, as it were, with that Spongie
substance, which I just now described.
This so oddly constituted Vegetable substance, is first (that I have met
with) taken notice of by _Baptista Porta_, in his _Natural Magick_, as a
thing known to children and Juglers, and it has been call’d by some of
those last named persons, the better to cover their cheat, the Legg of an
_Arabian Spider_, or the Legg of an inchanted _Egyptian fly_, and has been
used by them to make a small Index, Cross, or the like, to move round upon
the wetting of it with a drop of Water, and muttering certain words.
But the use that has been made of it, for the discovery of the various
constitutions of the Air, as to driness and moistness, is incomparably
beyond any other, for this it does to admiration: The manner of contriving
it so, as to perform this great effect, is onely thus:
Provide a good large Box of Ivory, about four Inches over, and of what
depth you shall judge convenient (according to your intention of making use
of one, two, three, or more of these small Beards, ordered in the manner
which I shall by and by describe) let all the sides of this Box be turned
of Basket-work (which here in _London_ is easily enough procur’d) full of
holes, in the manner almost of a Lettice, the bigger, or more the holes
are, the better, that so the Air may have the more free passage to the
inclosed Beard, and may the more easily pass through the Instrument; it
will be better yet, though not altogether so handsom, if insteed of the
Basket-work on the sides of the Box, the bottom and top of the Box be
join’d together onely with three or four small Pillars, after the manner
represented in the 4. Figure of the 15. _Scheme_. Or, if you intend to make
use of many of these small Beards join’d together, you may have a small
long Case of Ivory, whose sides are turn’d of Basket-work, full of holes,
which may be screw’d on to the underside of a broad Plate of Ivory, on the
other side of which is to be made the divided Ring or Circle, to which
divisions the pointing of the Hand or Index, which is moved by the
conjoin’d Beard, may shew all the _Minute_ variations of the Air.
There may be multitudes of other ways for contriving this small Instrument,
so as to produce this effect, which any one may, according to his peculiar
use, and the exigency of his present occasion, easily enough contrive and
take, on which I shall not therefore insist. The whole manner of making any
one of them is thus: Having your Box or frame AABB, fitly adapted for the
free passage of the Air through it, in the midst of the bottom BBB, you
must have a very small hole C, into which the lower end of the Beard is to
be fix’d, the upper end of which Beard ab, is to pass through a small hole
of a Plate, or top AA, if you make use onely of a single one, and on the
top of it e, is to be fix’d a small and very light _Index_ fg, made of a
very thin sliver of a Reed or Cane; but if you make use of two or more
Beards, they must be fix’d and bound together, either with a very fine
piece of Silk, or with a very small touch of hard Wax, or Glew, which is
better, and the _Index_ fg, is to be fix’d on the top of the second, third,
or fourth in the same manner as on the single one.
Now, because that in every of these contrivances, the _Index_ fg, will with
some temperatures of Air, move two, three, or more times round, which
without some other contrivance then this, will be difficult to distinguish,
therefore I thought of this Expedient: The _Index_ or _Hand_ fg, being
rais’d a pretty way above the surface of the Plate AA, fix in at a little
distance from the middle of it a small Pin h, so as almost to touch the
surface of the Plate AA, and then in any convenient place of the surface of
the Plate, fix a small Pin, on which put on a small piece of Paper, or thin
Pastboard, Vellom, or Parchment, made of a convenient cize, and shap’d in
the manner of that in the Figure express’d by ik, so that having a
convenient number of teeth every turn or return of the Pin h, may move this
small indented Circle, a tooth forward or backwards, by which means the
teeth of the Circle, being mark’d, it will be thereby very easie to know
certainly, how much variation any change of weather will make upon the
small wreath’d body. In the making of this Secundary Circle of Vellom, or
the like, great care is to be had, that it be made exceeding light, and to
move very easily, for otherwise a small variation will spoil the whole
operation. The Box may be made of Brass, Silver, Iron, or any other
substance, if care be taken to make it open enough, to let the Air have a
sufficiently free access to the Beard. The _Index_ also may be various ways
contrived, so as to shew both the number of the revolutions it makes, and
the _Minute_ divisions of each revolution.
I have made several trials and Instruments for discovering the driness and
moisture of the Air with this little wreath’d body, and find it to vary
exceeding sensibly with the least change in the constitution of the Air, as
to driness and moisture, so that with one breathing upon it, I have made 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, but 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 shrinking
in length, and also by their wreathing and unwreathing themselves; but
these are nothing neer so exact or so tender, for their varying property
will in a little time change very much. But there are several other
Vegetable substances that are much more sensible then even this Beard of a
wilde _Oat_; such I have found the Beard of the seed of Musk-grass, or
_Geranium moschatum_, and those of other kinds of _Cranes-bil_ seeds, and
the like. But always the smaller the wreathing substance be, the more
sensible is it of the mutations of the Air, a conjecture at the reason 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 moisture 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 to
re-twist; and wreath it self the contrary way, namely, from the East, (for
instance) by the North to the West, and so onwards.
The cause of all which _Phænomena_, seems to be the differing texture of
the parts of these bodies, each of them (especially the Beard of a wilde
_Oat_, and of _Mosk-grass_ seed) seeming to have two kind of substances,
one that is very porous, loose, and spongie, into which the watry steams of
the Air may be very easily forced, which will be thereby swell’d and
extended in its dimensions, just as we may observe all kind of Vegetable
substance upon steeping in water to swell and grow bigger and longer. And a
second that is more hard and close, 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 several sorts of
contrivances 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 cause it proceed, whether from gravity or weight, or from
wind which is motion of the Air, or from some springing body, or the like.
This, had I time, I should enlarge much more upon; for it seems to me to be
the very first footstep of _Sensation_, and Animate motion, the most plain,
simple, and obvious contrivance that Nature has made use of to produce a
motion; next to that of Rarefaction and Condensation by heat and cold. And
were this Principle very well examin’d, I am very apt to think, it would
afford us a very great help to find out the _Mechanism_ of the Muscles,
which indeed, as farr as I have hitherto been able to examine, seems to me
not so very perplex as one might imagine, especially upon the examination
which I made of the Muscles of _Crabs_, _Lobsters_, and several sorts of
large Shell-fish, and comparing my Observations on them, with the
circumstances I observ’d in the muscles of terrestrial Animals.
Now, as in this Instance of the Beard of a wilde _Oat_, we see there is
nothing else requisite to make it wreath and unwreath it self, and to
streighten and bend its knee, then onely a little breath of moist or dry
Air, or a small _atome_ almost of water or liquor, and a little heat to
make it again evaporate, for, by holding this Beard, plac’d and fix’d as I
before directed, neer a Fire, and dipping the tip of a small shred of Paper
in well rectify’d spirit of Wine, and then touching the wreath’d
_Cylindrical_ part, you may perceive it to untwist it self; and presently
again, upon the _avolation_ of the spirit, by the great heat, it will
re-twist it self, and thus will it move forward and backwards as oft as you
repeat the touching it with the spirit of Wine; so may, perhaps, the
shrinking and relaxing of the muscles be by the influx and evaporation of
some kind of liquor or juice. But of this Enquiry I shall add more
elsewhere.
* * * * *