SILVER TEXTURES, &c., OF THE ANCIENTS.
EXTREME BEAUTY OF THESE MANUFACTURES.
Magnificent dress worn by Herod Agrippa, mentioned in Acts xii.
21--Josephus’s account of this dress, and dreadful death of
Herod--Discovery of ancient Piece-goods--Beautiful manuscript
of Theodolphus, Bishop of Orleans, who lived in the ninth
century--Extraordinary beauty of Indian, Chinese, Egyptian, and other
manufactured goods preserved in this manuscript--Egyptian arts--Wise
regulations of the Egyptians in relation to the arts--Late discoveries
in Egypt by the Prussian hierologist, Dr. Lepsius--Cloth of glass.
The Evangelist Luke, in Acts xii. 21. speaks of the “royal apparel,”
in which Herod Agrippa, king of Judea, was arrayed when he received
the ambassadors of Tyre and Sidon, sitting in great state upon his
throne at Cæsarea. “And upon a set day, Herod arrayed in royal apparel,
sat upon his throne, and made an oration unto them. And the people
gave a shout, saying, It is the voice of a god, and not of a man. And
immediately the angel of the Lord smote him, because he gave not God
the glory: and he was eaten of worms, and gave up the ghost.”
Josephus describes the same garment, which was a tunic, as “all made
of _silver_, and wonderful in its texture.” He adds, that the king
appeared in this dress at break of day in the theatre, and that the
silver, illuminated by the first rays of the sun, glittered in such a
manner as to terrify the beholders, so that his flatterers began to
call out aloud, saluting him as a god. _He was then seized with the
painful and loathsome distemper, of which he soon after died[124]._
[124] _Ant. Jud._ L. xix. _cap._ 8. § 2. p. 871. _Hudson_.
We extract the following curious account of the discovery of Ancient
Piece-goods and manufactured stuffs from a late number of an English
publication called the “Mining Review.”
Discovery of ancient Piece-goods and manufactured stuffs.--“It is
more than a thousand years since Theodolphus, Bishop of Orleans, gave
to Notre Dame du Puy en Velay a beautiful manuscript, containing the
ancient Testament, the chronography of St. Isidor, and other pieces,
the whole distributed into 138 articles; which he presented in token
of gratitude for his deliverance from the prison of Angers, where he
was confined in the year 835. It was on Palm Sunday that year, while
Louis Le Debonnaire was passing, that he began to sing a well-known
Canticle, which the Catholic church _has since then_ introduced into
its ceremonies. This precious manuscript, in a state of perfect
preservation, is to be seen in the archives of the Bishopric of the Puy
en Velay, department of the Haute Loire. A portion of the manuscript
is written on leaves of common parchment, in letters of red and black,
with a few of gold intermixed. The other portion is inscribed on
leaves of parchment, dyed purple, with _letters of gold_ and _silver_,
among which are observed, ornaments of different kinds and colors,
designated the “_Byzantine style_.” The manuscript, remarkable for its
beauty and preservation, is still more valuable for the manufactured
stuffs which it contains. When Theodolphus composed his manuscript,
with the intention of preserving from contact and friction the gold
and silver characters (which, in time, would have tended to displace
and obliterate them), he placed between each page a portion of the
manufactured tissues peculiar to the era in which he lived. These
specimens of the silk, and other pieces of goods of the time are thus
curiously preserved[125]. Till lately, little attention was paid to
these tissues, which are principally of India manufacture, bearing
scarcely _any analogy_ to the products of the _modern loom_. Some are
CASHMERE SHAWLS of those patterns, which the French call _broucha_
and _espouline_, and are made in the Indian fashion, but with this
difference, that they are limited to _four_ colors, and demonstrate
the greatest antiquity by the primitive simplicity of their colors
and design. Others are CRAPES and GAUZES, against the luxury of
whose transparent tissues, the fathers of the church at that time so
perseveringly fulminated their censures. The rest consist of _muslins_
and _China-crape of exquisite beauty_. The components of the majority
of these tissues are of goats’ or camels’ hair of exceeding delicacy
and fineness. Like the manufactured stuffs of ancient Egypt, painted on
the walls of its palaces and tombs, or substantially preserved amidst
the envelopes of mummies, the designs are limited to four colors, which
are in fact the _four sacred ones of China_, _India_, _Egypt_, and the
_Hebrew Tabernacle_. Nevertheless, the Egyptian designs, _identical
with those of India_, are many of them of exquisite beauty. The
consummate skill of the silk and cotton manufacturers of ancient Egypt,
4000 years ago, _the beauty and richness of their fabrics_--the little
alteration which has taken place in the economy or machinery of the
factories, as well as in their product, has been recently demonstrated
in the great work of Champollion. All the details of the silk and
cotton factories of Egypt, under the Pharaohs of the 18th dynasty
(which then monopolized the commerce of the world, and sent a colony
of weavers, from the overburthened population of Lower Egypt, to found
Athens, and the subsequent civilization of Europe), are laid open with
vivid accuracy in that splendid work[126], and brought with all their
startling analogies before the eye of the modern reader by drawings
from the temples, palaces, and tombs which it contains. It proves,
indeed, that there is ”_nothing new under the sun_.”
[125] A shred of gold cloth is preserved in the Museum of Antiquities
at Leyden, which is supposed to have been discovered in one of the
ancient tombs at Tarquinia in Etruria. In this tissue the gold
forms a compact covering over bright yellow silk.
[126] See Plate II.
That the Egyptians excelled in science and art is evident from their
monuments, paintings, and sculptures, whereon they are depicted. It is
also proved by Scripture, which speaks of the “wisdom of Egypt” with
reference to art; and from the fact that Egypt was deemed by other
nations the fountain of arts and sciences, and that their philosophers
were wont to resort thither to collect some of the “droppings of
Egyptian wisdom.” According to Diodorus, all trades vied with each
other in improving their own particular branch, no pains being spared
to bring each to perfection. To promote the more effectually this
object, it was enacted that no artisan should follow any trade or
employment but that defined bylaw, and _pursued by his ancestors_. No
tradesman was permitted to meddle with political affairs, or hold any
civil office in the state, _lest his thoughts should be distracted by
the inconsistency of his pursuits_, or the jealousy and displeasure of
the master in whose service he was employed. They foresaw that without
such a law constant interruptions would take place, in consequence of
the necessity or desire of becoming conspicuous in a public station;
that their proper occupations would be neglected, and many would be
led by _vanity_ and _self-sufficiency_ to interfere in matters which
were out of their sphere. They considered, moreover, that to pursue
more than one avocation would be detrimental to their own interests,
and those of the community at large; and that, when men, from a motive
of avarice, engage in numerous branches of art, the general result
is, that they are unable to excel in any. If any artisan interfered
in political matters, or engaged in any employment other than the one
to which he had been brought up, a severe punishment was immediately
inflicted upon him.
The eminent German hierologist, Dr. Lepsius, now employed in Egypt by
the Prussian government, after mentioning, in a recent letter, the many
discoveries he had made of ancient ruins, tombs, &c., writes as follows:
“With the exception of about twelve, which belong to a later period,
all these tombs were erected contemporaneously with, or soon after,
the building of the great pyramid, and consequently their dates throw
an invaluable light on the study of human civilization in the most
remote period of antiquity. The _sculptures_ in relief are surprisingly
numerous, representing whole figures, some the size of life, and others
of various dimensions. The _paintings_ are on back grounds of the
finest chalk. They are numerous and beautiful beyond conception--_as
fresh and perfect as if finished yesterday_! The pictures and
sculptures on the walls of the tombs, represent, for the most part,
scenes in the lives of the deceased persons, whose wealth in cattle,
fish-boats, servants, &c., is ostentatiously displayed before the eye
of the spectator. All this gives an insight into the details of private
life among the ancient Egyptians. By the help of these inscriptions I
think I could, without difficulty, make a “Court Calendar” of the reign
of King Cheops[127]. In some instances I have traced the graves of
father, son, grandson, and even great-grandson--all that now remains of
the distinguished families, which five thousand years ago, formed the
nobility of the land.”
[127] We do not find in these researches, that the ancients were
acquainted with the arts of spinning and weaving glass, or of
giving it any required shade of color. This invention, therefore,
must be considered as belonging to the nineteenth century, and the
honor of the discovery is due to M. Dubus Bonnel, an ingenious
Frenchman, a native of Lille, and for which he obtained patents in
Great Britain, and various countries of the European continent in
1837.
“When we figure to ourselves an apartment decorated with cloth of
glass, and resplendent with lights, we must be convinced that it
will equal in brilliancy all that the imagination can conceive; and
realise, in a word, the wonders of the enchanted palaces mentioned
in the Arabian tales. The lights flashing from the polished
surface of the glass, to which any color or shade may be given,
will make the room have the appearance of an apartment composed of
pearls, mother-of-pearl, diamonds, garnets, sapphires, topazes,
rubies, emeralds, or amethysts, &c., or, in short, of all those
precious stones united and combined in a thousand ways, and formed
into stars, rosettes, boquets, garlands, festoons, and graceful
undulations, varied almost ad infinitum.”--L’Echo du Monde Savant,
&c. No. 58, Feb. 15, 1837.--_Translated from the French._
The warp is composed of silk, forming the body and groundwork on
which the pattern in glass appears, as effected by the weft. The
requisite flexibility of glass thread for manufacturing purposes
is to be ascribed to its extreme fineness; as not less than from
fifty to sixty of the original threads (spun by steam engine power)
are required to form one thread of the weft. The process is slow;
for no more than a yard of cloth can be produced in twelve hours.
The work, however, is extremely beautiful and comparatively cheap,
inasmuch as no similar stuff, where bullion is really introduced,
can be purchased for anything like the price for which this is
sold; added to this, it is, as far as the glass is concerned,
imperishable. Glass is more durable than either gold or silver,
and, besides, possesses the advantage of never tarnishing.
CHAPTER VII.
DESCRIPTION OF THE SILK-WORM, &c.
Preliminary observations--The silk-worm--Various changes of the
silk-worm--Its superiority above other worms--Beautiful verses on the
May-fly, illustrative of the shortness of human life--Transformations
of the silk-worm--Its small desire of locomotion--First sickness
of the worm--Manner of casting its Exuviæ--Sometimes cannot be
fully accomplished--Consequent death of the insect--Second, third,
and fourth sickness of the worm--Its disgust for food--Material of
which silk is formed--Mode of its secretion--Manner of unwinding the
filaments--Floss-silk--Cocoon--Its imperviousness to moisture--Effect
of the filaments breaking during the formation of the cocoon--Mr.
Robinet’s curious calculation on the movements made by a silk-worm
in the formation of a cocoon--Cowper’s beautiful lines on the
silk-worm--Periods in which its various progressions are effected
in different climates--Effects of sudden transitions from heat to
cold--The worm’s appetite sharpened by increased temperature--Shortens
its existence--Various experiments in artificial heating--Modes of
artificial heating--Singular estimate of Count Dandolo--Astonishing
increase of the worm--Its brief existence in the moth state--Formation
of silk--The silken filament formed in the worm before its
expulsion--Erroneous opinions entertained by writers on this
subject--The silk-worm’s Will.
It can never be too strongly impressed upon a mind anxious for the
acquisition of knowledge, that the commonest things by which we are
surrounded are deserving of minute and careful attention. The most
profound investigations of Philosophy are necessarily connected
with the ordinary circumstances of our being, and of the world in
which our every-day life is spent. With regard to our own existence,
the pulsation of the heart, the act of respiration, the voluntary
movement of our limbs, the condition of sleep, are among the most
ordinary operations of our nature; and yet how long were the wisest
of men struggling with dark and bewildering speculations before they
could offer anything like a satisfactory solution of these phenomena,
and how far are we still from an accurate and complete knowledge of
them! The science of Meteorology, which attempts to explain to us the
philosophy of matters constantly before our eyes, as dew, mist, and
rain, is dependent for its illustrations upon a knowledge of the most
complicated facts, such as the influence of heat and electricity upon
the air; and this knowledge is at present so imperfect, that even these
common occurrences of the weather, which men have been observing and
reasoning upon for ages, are by no means satisfactorily explained, or
reduced to the precision that every science should aspire to. Yet,
however difficult it may be entirely to comprehend the phenomena we
daily witness, everything in nature is full of instruction. Thus the
humblest flower of the field, although, to one whose curiosity has
not been excited, and whose understanding has, therefore, remained
uninformed, it may appear worthless and contemptible, is valuable to
the botanist, not only with regard to its place in the arrangement of
this portion of the Creator’s works, but as it leads his mind forward
to the consideration of those beautiful provisions for the support of
vegetable life, which it is the part of the physiologist to study and
admire[128].
[128] “Insect Architecture,” vol. i. p. 9. London: Charles Knight &
Co., Ludgate St. 1845.
This train of reasoning is peculiarly applicable to the economy of
insects. They constitute a very large and interesting part of the
animal kingdom. They are everywhere about us. The _spider_ weaves his
curious web in our houses; the _caterpillar_ constructs his silken cell
in our gardens; the _wasp_ that hovers over our food has a nest not
far removed from us, which she has assisted to build with the nicest
art; the _beetle_ that crawls across our path is also an ingenious and
laborious mechanic, and has some curious instincts to exhibit to those
who will feel an interest in watching his movements; and the _moth_
that eats into our clothes has something to plead for our pity, for he
came, like us, naked into the world, and he has destroyed our garments,
not in malice or wantonness, but that he may clothe himself with the
same wool which we have stripped from the sheep. An observation of
the habits of these little creatures is full of valuable lessons,
which the abundance of the examples has no tendency to diminish. The
more such observations are multiplied, the more we are led forward to
the freshest and the most delightful parts of knowledge; the more do
we learn to estimate rightly the extraordinary provisions and most
abundant resources of a creative Providence; and the better do we
appreciate our own relations with all the infinite varieties of Nature,
and our dependence, in common with the _ephemeron_ that flutters its
little hour in the summer sun, upon that Being in whose scheme of
existence the humblest as well as the highest creature has its destined
purposes. “If you speak of a _stone_,” says St. Basil, “if you speak
of a _fly_, a _gnat_, or a _bee_, your conversation will be a sort of
demonstration of his power whose hand formed them, for the wisdom of
the workman is commonly perceived in that which is of little size. He
who has stretched out the Heavens, and dug up the bottom of the sea, is
also He who has pierced a passage through the sting of the bee for the
ejection of its poison.”
If it be granted that making discoveries is one of the most
satisfactory of human pleasures, then we may without hesitation affirm,
that the study of insects is one of the most delightful branches of
natural history, for it affords peculiar facilities for its pursuit.
These facilities are found in the almost inexhaustible variety which
insects present to the curious observer.
There is, perhaps, no situation in which the lover of nature and the
observer of animal life may not find opportunities for increasing
his store of facts. It is told of a state prisoner under a cruel and
rigorous despotism, that when he was excluded from all commerce with
mankind, and was shut out from books, he took an interest and found
consolation in the visits of a _spider_; and there is no improbability
in the story. The operations of that persecuted creature are among the
most extraordinary exhibitions of mechanical ingenuity; and a daily
watching of the workings of its instinct would beget admiration in
a rightly constituted mind. The poor prisoner had abundant leisure
for the speculations in which the spider’s web would enchain his
understanding. We have all of us, at one period or other of our lives,
been struck with some singular evidence of contrivance in the economy
of insects, which we have seen with our own eyes. Want of leisure, and
probably want of knowledge, have prevented us from following up the
curiosity which for a moment was excited. And yet some such accident
has made men Naturalists, in the highest meaning of the term. Bonnet,
evidently speaking of himself, says, “I knew a naturalist, who, when
he was seventeen years of age, having heard of the operations of the
ant-lion, began by doubting them. He had no rest till he had examined
into them; and he verified them, he admired them, he discovered new
facts, and soon became the disciple and the friend of the Pliny of
France[129]” (Réaumur). It is not the happy
fortune of many to be able to devote themselves exclusively to
the study of nature, unquestionably the most fascinating of human
employments; but almost every one may acquire sufficient knowledge to
be able to derive a high gratification from beholding the more common
operations of animal life. His materials for contemplation are always
before him.
[129] Contemplation de la Nature, part ii. ch. 42.
The silk-worm is a species of caterpillar which, like all other
insects of the same class, undergoes a variety of changes during
the short period of its life; assuming, in each of three successive
transformations, _a form wholly dissimilar to that with which it was
previously invested_.
Among the great variety of caterpillars, the descriptions of which are
to be found in the records of natural history, the silk-worm occupies
a place far above the rest. Not only is our attention called to the
examination of its various transformations, by the desire of satisfying
our curiosity as entomologists, but our artificial wants incite us
likewise to the study of its nature and habits, that we may best and
most profitably apply its instinctive industry to our own advantage.
It has been well observed by Pullein, a writer on this subject, that
“there is scarcely anything among the various wonders which the animal
creation affords, more admirable than the variety of changes which the
silk-worm undergoes;” but the curious texture of that silken covering
with which it surrounds itself when it arrives at the perfection of
its animal life, vastly surpasses what is made by other animals of
this class. All the caterpillar kind do, indeed, pass through changes
like those of the silk-worm, and the beauty of many in their butterfly
state greatly exceeds it; but the covering which they put on before
this mutation is poor and mean, when compared to that golden tissue in
which the silk-worm wraps itself. They, indeed, come forth in a variety
of colors, their wings bedropped with gold and scarlet, yet are they
but the beings of a summer’s day; both their life and beauty quickly
vanish, and they leave no remembrance after them; but the silk-worm
leaves behind it such beautiful, such beneficial monuments, as at once
to record both the wisdom of their Creator and his bounty to man.”
We may without impropriety, here introduce the following truly
beautiful comparison of the shortness of human life, as well as in
illustration of this part of our subject, as evidenced in the May-fly.
“The angler’s May-fly, the most short-lived in its perfect state of
any of the insect race, emerges from the water, where it passes its
_aurelia_ state, about six in the evening, and dies about eleven at
night.”--WHITE’S _Selborne_.
The sun of the eve was warm and bright
When the May-fly burst his shell,
And he wanton’d awhile in that fair light
O’er the river’s gentle swell;
And the deepening tints of the crimson sky
Still gleam’d on the wing of the glad May-fly.
The colors of sunset pass’d away,
The crimson and yellow green,
And the evening-star’s first twinkling ray
In the waveless stream was seen;
Till the deep repose of the stillest night
Was hushing about his giddy flight.
The noon of the night is nearly come--
There’s a crescent in the sky;--
The silence still hears the myriad hum
Of the insect revelry.
The hum has ceas’d--the quiet wave
Is now the sportive May-fly’s grave.
Oh! thine was a blessed lot--to spring
In thy lustihood to air,
And sail about, on untiring wing,
Through a world most rich and fair,
To drop at once in thy watery bed,
Like a leaf that the willow branch has shed.
And who shall say that his thread of years
Is a life more blest than thine!
Has his feverish dream of doubts and fears
Such joys as those which shine
In the constant pleasures of thy way,
Most happy child of the happy May?
For thou wert born when the earth was clad
With her robe of buds and flowers,
And didst float about with a soul as glad
As a bird in the sunny showers;
And the hour of thy death had a sweet repose,
Like a melody, sweetest at its close.
Nor too brief the date of thy cheerful race--
’Tis its use that measures time--
And the mighty Spirit that fills all space
With His life and His will sublime,
May see that the May-fly and the Man
Each flutter out the same small span;
And the fly that is born with the sinking sun,
To die ere the midnight hour,
May have deeper joy, ere his course be run,
Than man in his pride and power;
And the insect’s minutes be spared the fears
And the anxious doubts of our threescore years.
The years and the minutes are as one--
The fly drops in his twilight mirth,
And the man, when his long day’s work is done,
Crawls to the self-same earth.
Great Father of each! may _our_ mortal day
Be the prelude to an endless May[130]!
[130] “See,” exclaims Linnæus, “the large, elegant painted wings of
the butterfly, four in number, covered with delicate feathery
scales! With these it sustains itself in the air a whole day,
rivalling the flight of birds and the brilliancy of the peacock.
Consider this insect through the wonderful progress of its
life,--how different is the first period of its being from the
second, and both from the parent insect! Its changes are an
inexplicable enigma to us: we see a green caterpillar, furnished
with sixteen feet, feeding upon the leaves of a plant; this is
changed into a chrysalis, smooth, of golden lustre, hanging
suspended to a fixed point, without feet, and subsisting without
food; this insect again undergoes another transformation, acquires
wings, and six feet, and becomes a gay butterfly, sporting in
the air, and living by suction upon the honey of plants. What
has Nature produced more worthy of our admiration than such an
animal coming upon the stage of the world, and playing its part
there under so many different masks?” The ancients were so struck
with the transformations of the butterfly, and its revival from
a seeming temporary death, as to have considered it an emblem of
the soul, the Greek word _psyche_ signifying both the soul and a
butterfly; and it is for this reason that we find the butterfly
introduced into their allegorical sculptures as an emblem of
immortality. Trifling, therefore, and perhaps contemptible, as
to the unthinking may seem the study of a butterfly, yet when
we consider the art and mechanism displayed in so minute a
structure,--the fluids circulating in vessels so small as almost
to escape the sight--the beauty of the wings and covering--and
the manner in which each part is adapted for its peculiar
functions,--we cannot but be struck with wonder and admiration, and
allow, with Paley, that “the production of beauty was as much in
the Creator’s mind in painting a butterfly as in giving symmetry to
the human form.”
Silk-worms proceed from eggs which are deposited during the summer by a
grayish kind of moth, of the genus palæna. These eggs are about equal
in size to a grain of mustard seed: their color when first laid is
yellow; but in three or four days after, they acquire a bluish cast.
In temperate climates, and by using proper precautions, these eggs may
be preserved during the winter and spring, without risk of premature
hatching. The period of their animation may be accelerated or retarded
by artificial means, so as to agree with the time when the natural food
of the insect shall appear in ample abundance for its support.
All the curious changes and labors which accompany and characterize
the life of the silk-worm are performed within the space of a very
few weeks. This period varies, indeed, according to the climate or
temperature in which its life is passed; all its vital functions being
quickened, and their duration proportionally abridged, by warmth. With
this sole variance, its progressions are alike in all climates, and the
same mutations accompany its course.
The three successive states of being put on by this insect are, that
of the worm or caterpillar, of the chrysalis or aurelia, and moth. In
addition to these more decided transformations, the progress of the
silk-worm in its _caterpillar state_ is marked by _five distinct stages
of being_.
When first hatched, it appears as a small black worm about a quarter
of an inch in length. Its first indication of animation is the desire
which it evinces for obtaining food, in search of which, if not
immediately supplied, it will exhibit more power of locomotion than
characterizes it at any other period. So small is the desire of change
on the part of these insects, that of the generality it may be said,
their own spontaneous will seldom leads them to travel over a greater
space than three feet throughout the whole duration of their lives.
Even when hungry, the worm still clings to the skeleton of the leaf
from which its nourishment was last derived. If, by the continued
cravings of its appetite, it should be at length incited to the effort
necessary for changing its position, it will sometimes wander as far
as the edge of the tray wherein it is confined, and some few have been
found sufficiently adventurous to cling to its rim; but the smell of
fresh leaves will instantly allure them back. It would add incalculably
to the labors and cares of their attendants, if silk-worms were endowed
with a more rambling disposition. So useful is this peculiarity of
their nature, that one is irresistibly tempted to consider it the
result of design, and a part of that beautiful system of the fitness of
things, which the student of natural history has so many opportunities
of contemplating with delight and admiration.
In about eight days from its being hatched, its head becomes
perceptibly larger, and the worm is attacked by its first sickness.
This lasts for three days; during which time it refuses food, and
remains motionless as in a kind of lethargy. Some have thought this
to be sleep, but the fatal termination which so frequently attends
these sicknesses seems to afford a denial to this hypothesis. The
silk-worm increases its size so considerably, and in so short a space
of time,--its weight being multiplied many thousand fold in the course
of one month,--that if only one skin had been assigned to it, which
should serve for its whole caterpillar state, it would with difficulty
have distended itself sufficiently to keep pace with the insect’s
growth. The economy of nature has therefore admirably provided the
embryos of other skins, destined to be successively called into use;
and this sickness of the worm, and its disinclination for food, may
very probably be occasioned by the pressure of the skin, now become too
small for the body which it encases.
At the end of the third day from its first refusal of food, the
animal appears, on that account, much wasted in its bodily frame; a
circumstance which materially assists in the painful operation of
casting its skin: this it now proceeds to accomplish. To facilitate
this moulting, a sort of humor is thrown off by the worm, which,
spreading between its body and the skin about to be abandoned,
lubricates their surfaces, and causes them to separate the more
readily. The insect also emits from its body silken traces, which,
adhering to the spot where it rests, serves to confine the skin to
its then existing position. These preliminary steps seem to call for
some considerable exertion, as after them the worm remains quiet for a
short space of time, to recover from its fatigue. It then proceeds, by
rubbing its head among the leafy fibres surrounding it, to disencumber
itself of the scaly covering. Its next effort is to break through the
skin nearest to the head, which, as it is there the smallest, calls for
the greatest exertion; and no sooner is this accomplished and the two
front legs are disengaged, than the remainder of the body is quickly
drawn forth, the skin being still fastened to the spot in the manner
already described.
This moulting is so complete, _that not only is the whole covering of
the body cast off, but that of the feet, the entire skull, and even
the jaws, including the teeth_. These several parts may be discerned
by the unassisted eye; but become very apparent when viewed through a
magnifying lens of moderate power.
In two or three minutes from the beginning of its efforts the worm is
wholly freed, and again puts on the appearance of health and vigor;
feeding with recruited appetite upon its leafy banquet. It sometimes
happens that the outer skin refuses to detach itself wholly, but breaks
and leaves an annular portion adhering to the extremity of its body,
from which all the struggles of the insect cannot wholly disengage it.
The pressure thus occasioned induces swelling and inflammation in other
parts of the body; and, after efforts of greater or less duration,
death generally terminates its sufferings.
Worms newly freed from their exuviæ are easily distinguished from
others by the pale color and wrinkled appearance of their new skin.
This latter quality, however, soon disappears, through the repletion
and growth of the insect, which continues to feed during five days.
At this time its length will be increased to half an inch; when it
is attacked by a second sickness, followed by a second moulting, the
manner of performing which is exactly similar to the former. Its
appetite then again returns, and is indulged during other five days, in
the course of which time its length increases to three quarters of an
inch: it then undergoes its third sickness and moulting. These being
past in all respects like the former, and five more days of feeding
having followed, it is seized by its fourth sickness, and casts its
skin for the last time in the caterpillar state. The worm is now about
one and a half or two inches long. This last change being finished, the
worm devours its food most voraciously, and increases rapidly in size
during ten days.
The silk-worm has now attained to its full growth, and is a slender
caterpillar from two and a half to three inches in length (See Figure
1. Plate III.). The peculiarities of its structure may be better
examined now than in its earlier stages. It can readily be seen that
the worm has twelve membranous rings round its body, parallel to each
other; and which, answering to the movements of the animal, mutually
contract and elongate. It has sixteen legs, in pairs: six in front,
which are covered with a sort of shell or scale, and are placed under
the three first rings, and cannot be either sensibly lengthened, or
their position altered. The other ten legs are called holders: these
are membranous, flexible, and attached to the body under the rings,
being furnished with little hooks, which assist the insect in climbing.
The skull is inclosed in a scaly substance, similar to the covering of
the first six legs. The jaws are indented or serrated like the teeth of
a saw, and their strength is great considering the size of the insect.
Its mouth is peculiar, having a vertical instead of an horizontal
aperture; and the worm is furnished with eighteen breathing holes,
placed at equal distances down the body, nine on each side. Each of
these holes is supposed to be the termination of a particular organ of
respiration. On either side of the head, near to the mouth, seven small
eyes may be discerned. The two broad appearances higher upon the head,
which are frequently mistaken for eyes, are bones of the skull. The two
apertures through which the worm draws its silken filament are placed
just beneath the jaw, and close to each other; these being exceedingly
minute.
At the period above-mentioned the desire of the worm for food begins
to abate: the first symptom of this is the appearance of the leaves
nibbled into small portions and wasted. It soon after entirely ceases
even to touch the leaves; appears restless and uneasy; erects it head;
and moves about from side to side, with a circular motion, in quest of
a place wherein it can commence its labor of spinning. Its color is now
light green, with some mixture of a darker hue. In twenty-four hours
from the time of its abstaining from food, the material for forming
its silk will be digested in its reservoirs; its green color will
disappear; its body will have acquired a degree of glossiness, and have
become partially transparent towards its neck. Before the worm is quite
prepared to spin, its body will have acquired greater firmness, and be
in a trifling measure lessened in size.
“The substance,” says Mr. Porter, “of which the silk is composed, _is
secreted in the form of a fine yellow transparent gum in two separate
vessels of slender dimensions, wound, as it were, on two spindles in
the stomach; and if unfolded, these vessels would be about ten inches
in length_[131].” This statement is proved to be erroneous, as the
reader will perceive, at the conclusion of this chapter.
[131] Porter’s “Treatise on the Silk Manufacture,” p. 111.
When the worm has fixed upon some angle, or hollow place, whose
dimensions agree with the size of its intended silken ball or cocoon,
it begins its labor by throwing forth thin and irregular threads, see
Figure 2. Plate III., which are intended to support its future dwelling.
During the first day, the insect forms upon these a loose structure of
an oval shape, which is called floss silk, and within which covering,
in the three following days, it forms the firm and consistent yellow
ball; the laborer, of course, always remaining on the inside of the
sphere which it is forming[132].
[132] If at this time any of the threads intended for the support of
the cocoon should be broken, the worm will find, in the progress
of its work, that the ball, not being properly poised, becomes
unsteady, so that the insect is unable properly to go forward
with its labors. Under these circumstances the worm pierces
and altogether quits the unfinished cocoon, and throws out its
remaining threads at random wherever it passes; by which means the
silk is wholly lost, and the worm, finding no place wherein to
prepare for its change, dies without having effected it. It may
sometimes happen, but such a thing is of unfrequent occurrence,
that the preparatory threads before mentioned are broken by another
worm working in the neighborhood, when the same unsatisfactory
result will be experienced.--_Obs. on the Culture of Silk_, _by_ A.
STEPHENSON.
The silken filament, which when drawn out appears to be one thread,
is composed of two fibres, unwound through the two orifices before
described; and these fibres are brought together by means of two hooks,
placed within the silk-worm’s mouth for the purpose. The worm rests on
its lower extremity throughout the unwinding operation, and employs
its mouth and front legs in the task of directing and uniting the two
filaments. The filament is not wound in regular concentric circles
round the interior surface of the ball, but in spots, going backwards
and forwards with a sort of wavy motion. This apparently irregular
manner of proceeding is plainly perceptible when the silk is being
reeled off the ball; which does not make more than one or two entire
revolutions while ten or twelve yards of silk are being transferred to
the reel[133].
[133] Mr. Robinet, of Paris, made the following curious calculation
on the movements a silk-worm must make in forming a cocoon supposed
to contain a thread of 1500 metres. It is known, says Mr. Robinet,
that the silk-worm, in forming his cocoon, does not _spin_ the
silken filament in concentric circles round the interior surface of
the ball, but in a zigzag manner. This it effects by the motions of
its head. Now if each one of these motions gives half a centimetre
of the silken filament; it follows that the worm must make 300,000
motions of its head to form it; and if the labor requires 72 hours
in the performance, the creature makes 100,000 motions every 24
hours, 4,166 per hour, 69 per minute, and a little more than one in
a second!
At the end of the third or fourth day, the worm will have completed
its task; and we have then a _silk cocoon_ (See Figure 3. Plate III.),
with the worm imprisoned in its centre; the cocoon being from an inch
to an inch and a half long, and of a yellow or orange color.
When the insect has finished its labor of unwinding, it smears the
entire internal surface of the cocoon with a peculiar kind of gum, very
similar in its nature to the matter which forms the silk itself; and
this is no doubt designed as a shield against rain or the humidity of
the atmosphere, for the chrysalis in its natural state; when of course
it would be subject to all varieties of weather. The silken filament
of which the ball is made up, is likewise accompanied, throughout its
entire length, by a portion of gum, which serves to give firmness and
consistency to its texture; and assists in rendering the dwelling of
the chrysalis impervious to moisture. This office it performs so well,
that when, for the purpose of reeling the silk with greater facility,
the balls are thrown into basins of hot water, they swim on the top
with all the buoyancy of bladders; nor, unless the ball be imperfectly
formed, does the water penetrate within until the silk is nearly all
unwound. In figure 4, plate III., the cocoons are drawn two-thirds
of the usual size, and are shown with part of the outward floss silk
removed.
The continual emission of the silken material during the formation of
its envelope, together with its natural evaporation, uncompensated
by food, causes the worm gradually to contract in bulk; it becomes
wrinkled, and the rings of its body approach nearer to each other and
appear more decidedly marked. When the ball is finished, the insect
rests awhile from its toil, and then throws off its caterpillar garb.
If the cocoon be now opened, its inhabitant will appear in the form of
a chrysalis or aurelia, in shape somewhat resembling a kidney-bean (See
Figure 5. plate III.), but pointed at one end, having a smooth brown
skin. Its former covering, so dissimilar to the one now assumed, will
be found lying beside it.
The account which has been given of the progressions of the silk-worm
shows, that, in its various modifications, _the animal organization of
the insect has been always tending towards its simplification_. Count
Dandolo, writing upon this subject, observes, “Thus the caterpillar
is in the first instance composed of animal, silky, and excremental
particles; this forms the state of the _growing caterpillar_: in the
next stage it is composed of animal and silky particles; it is then the
_mature caterpillar_: and lastly, it is reduced to the animal particles
alone; and is termed in this state the _chrysalis_. The poet Cowper, in
the following lines, beautifully illustrates this subject:
The beams of April, ere it goes,
A worm, scarce visible, disclose;
All winter long content to dwell
The tenant of his native shell.
The same prolific season gives
The sustenance by which he lives,
The mulberry leaf, a simple store,
That serves him--till he needs no more!
For, his dimensions once complete,
Thenceforth none ever sees him eat;
Though till his growing time be past
Scarce ever is he seen to fast.
That hour arrived, his work begins.
He spins and weaves, and weaves and spins;
Till circle upon circle, wound
Careless around him and around,
Conceals him with a veil though slight,
Impervious to the keenest sight.
Thus self-inclosed, as in a cask,
At length he finishes his task:
And, though a worm when he was lost,
Or caterpillar at the most,
When next we see him, wings he wears,
And in papilio pomp appears;
Becomes oviparous; supplies
With future worms and future flies
The next ensuing year--and dies!
Well were it for the world if all
Who creep about this earthly ball,
Though shorter-lived than most he be,
Were useful in their kind as he.
It has been already noticed that the progressions of the insects are
accelerated by an increase of temperature; and some variation will
equally be experienced where different modes of treatment are followed;
and, in particular, where different periods of the year are chosen in
which to produce and rear the worm. Malpighius, in his “Anatomy of the
Silk-worm,” says, that worms which he hatched in May were eleven days
old ere they were attacked by their first sickness; others hatched in
July were ten days, and those brought forth in August nine days, before
they refused their food, preparatory to their first moulting. Eight
days appear to be the most usual term for their first attack; and by
his judicious treatment count Dandolo shortened even this term by two
days. In Europe, except where recourse is had to artificial aid, the
term of the caterpillar state is usually that which has been already
mentioned.
Sudden transitions from cold to heat, or vice versa, are highly
injurious to the silk-worm; but it can bear a very high degree of heat,
if uniformly maintained, without sustaining injury. Count Dandolo
observed, that “the greater the degree of heat in which it is reared,
the more acute are its wants, the more rapid its pleasures, and the
shorter its existence.” Monsieur Boissier de Sauvagues made many
experiments on this point. One year, when by the early appearance of
the mulberry leaves, which were developed by the end of April, he was
forced to hurry forward the operations of his filature, he raised the
heat of the apartment in which the newly-hatched worms were placed to
100°; gradually diminishing this during their first and second ages
to 95°. In consequence of the animal excitement thus induced, there
elapsed only nine days between the hatching and the second moulting
inclusively. It was the general opinion of those cultivators who
witnessed the experiment, that the insects would not be able to exist
in so intensely heated an atmosphere. The walls of the apartment, and
the wicker hurdles on which the worms were placed, could scarcely be
touched from the great heat, and yet all the changes and progressions
went forward perfectly well, and a most abundant crop of silk was the
result.
The same gentleman, on a subsequent occasion, exposed his brood to the
temperature of 93° to 95° during their first age; of 89° to 91° in the
second age; and remarked that the attendant circumstances were the same
as in his former experiment, the changes of the worm being performed
in the same space of time; whence he came to the conclusion, that
it is not practicable to accelerate their progress beyond a certain
point by any superadditions of heat. In both of these experiments the
quantity of food consumed, was as great as is usually given during
the longer period employed in the common manner of rearing. After the
second moulting had taken place in the last experiment, the temperature
was lowered to 82°; and it is remarkable that the worms occupied only
five days in completing their third and fourth changes, although
others which had been accustomed to this lower degree from their birth
occupied seven or eight days for each of these moultings. It would
therefore seem that the constitution of the insects can be affected,
and an impetus given to their functions at the period of their first
animation, which accompanies them through their after stages. So far
from this forcing system proving injurious to the health of silk-worms,
M. de Sauvagues found that his broods were unusually healthy; and that
while the labors of cultivation were abridged in their duration, much
of the attendant anxiety was removed.
Like other caterpillars, the silk-worm is not a warm-blooded
animal, and its temperature is therefore always equal to that of the
atmosphere in which it is placed. In the silk-producing countries,
where modes of artificial heating have not been studied practically
and scientifically, the difficulty and expense that must attend
the prosecution of this heating system, form abundant reasons why
it cannot be generally adopted. The great susceptibility of the
insect to atmospheric influences would also in a great degree render
unsuitable the more common arrangements for the purpose. The plan
of warming apartments by means of stoves, in its passage through
which the air becomes highly heated before it mixes with and raises
the general temperature of the air in the chamber, is liable to
this inconvenience,--that the portion so introduced, having its
vital property impaired by the burning heat through which it has
passed, injures, proportionably, the respirable quality of the whole
atmosphere; an effect which is easily perceptible by those who inhale
it. A better plan of heating has lately been suggested, and is rapidly
coming into practice, viz., of warming buildings by a current of hot
water (an American invention), which is, by a very simple process, kept
constantly flowing in close channels through the apartment, where it
continually gives off its heat by radiation; and the degree of this
being far below the point which is injurious to the vital quality of
air, the evil before alluded to is avoided. If the expense of fuel
be not too great, as compared with that of the labor which would be
saved by this invention, the adoption in silk countries of such a
mode of raising and regulating the temperature might, probably, prove
advantageous.
The silk-worm remains in the form of a chrysalis, for periods which,
according to the climate or the temperature wherein it may be placed,
vary from fifteen to thirty days. In India, the time is much shorter
(See Chapter VIII.); in Spain and Italy, eighteen to twenty days. In
France three weeks; and in the climate of England, when unaccelerated
by artificial means, thirty days will elapse from the time the insect
begins to spin until it emerges in its last and perfect form. It then
throws off the shroud which had confined it in _seeming lifelessness_,
and appears as a large moth of a grayish-white color, furnished with
four wings, two eyes, and two black horns or antlers which present a
feathery appearance (See Figure 6. plate III.).
If left until this period within the cocoon, the moth takes immediate
measures for its extrication: ejecting from its mouth a liquor with
which it moistens and lessens the adhesiveness of the gum wherewith
it had lined the interior surface of its dwelling, and the insect is
enabled, by frequent motions of its head, to loosen, without breaking,
the texture of the ball; then using its hooked feet, it pushes aside
the filaments and makes a passage for itself into light and freedom.
It is erroneously said that the moth recovers its liberty by gnawing
the silken threads; but it is found, on the contrary, that if carefully
unwound, their continuity is by this means rarely broken.
One of the most remarkable circumstances connected with the natural
history of silk-worms, is the degree in which their bulk and weight
is increased, and the limited time wherein that increase is attained.
Count Dandolo, who appears to have neglected nothing that could tend
to the right understanding of the subject, and to the consequent
improvement of the processes employed, had patience enough to count
and weigh many hundred thousand eggs, as well as follow out to the
ultimate result his inquiries respecting their produce. He found that
on an average sixty-eight sound silk-worm’s eggs weighed one grain.
One ounce[134], therefore, comprised, 39,168 eggs. But one twelfth
part of this weight evaporates previous to hatching, and the shells
are equal to one fifth more. If, therefore, from one ounce, composed
of 576 grains, 48 grains be deducted for evaporation, and 115 for the
shells, 413 grains will remain equal to the weight of 39,168 young
worms; and, at this rate, 54,526 of the insects when newly hatched, are
required to make up the ounce. After the first casting of the skin,
3840 worms are found to have this weight, so that the bulk and weight
of the insects have in a few days been multiplied more than _fourteen
times_. After the second change 610 worms weigh an ounce, their weight
being increased in the intermediate time six fold. In the week passed
between the second and third ages, the number of insects required to
make up the same weight, decreases from 610 to 144, their weight being
therefore more than quadrupled. During the fourth age, a similar rate
of increase is maintained: thirty-five worms now weigh an ounce. The
fifth age of the caterpillar comprises nearly a third part of its brief
existence, and has been described, by an enthusiastic writer on the
subject, as the happiest period of its life, during which it rapidly
increases in size, preparing and secreting the material it is about to
spin. When the silk-worms are fully grown, and have arrived at their
period of finally rejecting food, six of them make up the weight of an
ounce. They have, therefore, since their last change, again added to
their weight _six fold_.
[134] This ounce contains 576 grains; 8.5325 of these grains equal
seven grains troy. One ounce avoirdupoise is therefore equal to
about 533 grains, and between 11-12 and 11-13 ounce avoirdupoise
equals one of the above ounces.
It is thus seen that, in a few short weeks, the insect has multiplied
its weight more than _nine thousand fold_! From this period, and during
the whole of its two succeeding states of being, the worm imbibes no
nourishment, and gradually diminishes in weight; being supported by its
own substance, and appearing to find sufficient occupation in forming
its silken web, and providing successors for our service, without
indulging that grosser appetite which forms the beginning and the end
of their desires during their caterpillar existence.
The moth enjoys its liberty for only a very brief space. Its first
employment is to seek its mate; after which the female deposits her
eggs; and both in the course of two or three days after, end their
being.
Formation of Silk. By M. H. Straus, of Durckheim.--“It is generally
admitted by naturalists that the thread of the caterpillar is
produced by a simple emission of liquid matter through the orifice of
the spinner, and that it acquires solidity at once from the drying
influence of the air. It was easy to entertain such an hypothesis,
for nothing is more simple than the formation of a very fine thread
by such a process. But a little reflection will soon show us, even _à
priori_, that it is not possible; for how can we comprehend that so
fine a fibre, liquid at the instant of its issue from the aperture,
should _instantly_ acquire such a consistence as to bear the weight of
the animal suspended by it, and at the same time that it is rapidly
produced? Though the fluid, holding the silk in solution, should be
quickly volatilised, it must still be a matter of conjecture, how the
animal suspended by this thread could be able to arrest its issue,
holding on only by the thread itself, for it cannot pinch the thread,
seeing that it is only in a liquid state inside, and the thread cannot
be glued to the edge of the opening, as its rapid adhesion would
prevent its issue while the animal is spinning. A little examination
would satisfy us that silk cannot be produced in this manner, but that
it is secreted in the _form of silk_ in the silk vessels, and that
the spinning apparatus _only winds it_. The thread is produced in the
slender posterior part of the vessel, the inflated portion of which
consists of the reservoir of ready formed silk, where it is found in
the form of a skein; each thread being rolled up so as to occupy in the
silk-worm (_Bombex mori_) a space of only about a sixth part of the
real length of the skein. The fact is shown by the following experiment
I made for the purpose of ascertaining whether the silk is formed in
the body of the caterpillars.
‘_Take one of the animals when about to form its cocoon, clean it in
common vinegar, in which it may remain from four to six hours, open it
on the back and extract the silk vessels, there being one on each side
of the alimentary canal. Take them up by the hinder end, just where
they begin to swell (further back the silk is not solid enough), and
draw them out. The membrane forming the vessel is easily torn open,
and the contents expand to six or seven times its original length.
The skein having attained its full length by the letting out of its
gathers, we obtain a cord perfectly equal in size throughout, except
at the end, where it is attenuated._ This cord resembles a large
horse-hair, and constitutes what fishermen call “_Florence hair_.” I
ought to add that in simply drawing out the silk vessel, the Florence
hair is found enveloped in a golden yellow gummy matter, forming the
glutinous portion by which the worm fastens its thread. This must be
got rid of by drawing the cord through the fold formed on the inside of
the joint of the left fore finger, converted into a canal by applying
to it the end of the thumb. The glutinous substance and the membranes
being thus separated, we have the _naked hair_. In this state, before
the silk becomes dry and hard, not only will it be indefinitely divided
longitudinally, which proves its fibrous structure, but in trying to
split it by drawing it transversely, _the little filaments of silk
which form it are perfectly separated_, making _a bundle of extremely
fine fibrils_.’
We cannot better conclude this interesting portion of our subject, than
by quoting the following beautiful lines by Miss H. F. Gould:--
THE SILK-WORM’S WILL.
On a plain rush hurdle a silk-worm lay,
When a proud young princess came that way:
The haughty child of a human king,
Threw a sidelong glance at the humble thing,
That took, with a silent gratitude,
From the mulberry leaf, her simple food;
And shrunk, half scorn and half disgust,
Away from her sister child of dust--
Declaring she never yet could see
Why a reptile form like this should be,
And that she was not made with nerves so firm,
As calmly to stand by a “crawling worm!”
With mute forbearance the silk-worm took
The taunting words, and the spurning look:
Alike a stranger to self and pride,
She’d no disquiet from aught beside--
And lived of a meekness and peace possessed,
Which these debar from the human breast.
She only wished, for the harsh abuse,
To find some way to become of use
To the haughty daughter of lordly man;
And thus did she lay a noble plan,
To teach her wisdom, and make it plain,
That the humble worm was not made in vain;
A plan so generous, deep and high,
That, to carry it out, she must even die!
“No more,” said she, “will I drink or eat!
I’ll spin and weave me a winding-sheet,
To wrap me up from the sun’s clear light,
And hide my form from her wounded sight.
In secret then, till my end draws nigh,
I’ll toil for her; and when I die,
I’ll leave behind, as a farewell boon,
To the proud young princess, my whole cocoon,
To be reeled and wove to a shining lace,
And hung in a veil o’er her scornful face!
And when she can calmly draw her breath
Through the very threads that have caused my death;
When she finds, at length, she has nerves so firm
As to wear the shroud of a crawling worm,
May she bear in mind, that she walks with pride
In the winding-sheet where the silk-worm died!”
[Illustration:
_Plate III_
Silk-Worm, Cocoons, Chrysalis, Moths and Pinna.]
CHAPTER VIII.
GENERAL OBSERVATIONS ON THE CHINESE MODE OF REARING SILK-WORMS, &c.
Great antiquity of the silk-manufacture in China--Time and mode
of pruning the Mulberry-tree--Not allowed to exceed a certain
height--Mode of planting--Situation of rearing-rooms, and their
construction--Effect of noise on the silk-worm--Precautions observed
in preserving cleanliness--Isan-mon, mother of the worms--Manner
of feeding--Space allotted to the worms--Destruction of the
Chrysalides--Great skill of the Chinese in weaving--American writers
on the Mulberry-tree--Silk-worms sometimes reared on trees--(M.
Marteloy’s experiments in 1764, in rearing silk-worms on trees in
France)--Produce inferior to that of worms reared in houses--Mode of
delaying the hatching of the eggs--Method of hatching--Necessity for
preventing damp--Number of meals--Mode of stimulating the appetite of
the worms--Effect of this upon the quantity of silk produced--Darkness
injurious to the silk-worm--Its effect on the Mulberry-leaves--Mode
of preparing the cocoons for the reeling process--Wild silk-worms of
India--Mode of hatching, &c.--(Observations on the cultivation of silk
by Dr. Stebbins--Dr. Bowring’s admirable illustration of the mutual
dependence of the arts upon each other.)
In China, the tradition of the silk culture is, as already shown,
carried back into the mythological periods, and dates with the origin
of agriculture itself. These two pursuits or avocations, namely,
husbandry and the silk-manufacture, form the subject of one of the
sixteen discourses to the people. It is there observed, that “from
ancient times the Son of Heaven directed the plough: the Empress
planted the mulberry-tree. Thus have these exalted personages, not
_above_ the practice of labor and exertion, set an example to all men,
with a view to leading the millions of their subjects to attend to
their essential interests.”
In the work published by Imperial authority, entitled “Illustrations of
Husbandry and Weaving[135],” there are numerous wood-cuts, accompanied
by letter-press explanatory of the different processes of farming and
the silk-manufacture. The former head is confined to the production
of rice, the staple article of food, and proceeds from the ploughing
of the land to the packing of the grain; the latter details all the
operations connected with planting the mulberry and gathering its
leaves, up to the final weaving of the silk.
[135] The drawing, plate I. (Frontispiece) is a faithful copy of a loom
represented in this curious work. For this representation of
a Chinese weaving engine, as well as several translations,
explanatory of the silk-manufacture, &c., we are indebted to Walter
Lowry, Esq., Sec. to the Presbyterian Board of Foreign Missions in
this city; who kindly permitted us to copy it from the original
plate, forming a part of the interesting work above referred
to, which is composed of seventy-five volumes, and was, as we
understand, presented to the Board by a New York merchant. Many of
the illustrations are extremely beautiful, reflecting the highest
credit upon the artisans of the “Celestial Empire.”
The mulberry-tree is chiefly cultivated in Chĕ-kiang, which
province, together with the only three others that produce fine
silk, namely, Kiang-nân, Woo-pĕ, and Sze-chuen, is crossed by the
_thirtieth_ parallel of latitude. Chĕ-kiang is a country highly
alluvial, intersected by numerous rivers and canals, with a climate
that corresponds pretty nearly to the same latitude as that in the
United States of America. The soil is manured with mud, dug from the
rivers, assisted with ashes or dung; and the spaces between the trees
are generally filled with millet, pulse, or other articles of food. The
time for pruning the young trees, so as to produce fine leafy shoots,
is at the commencement of the year. About four eyes are left on every
shoot, and care is taken that the branches be properly thinned, with
a view to giving plenty of light and air to the leaves. In gathering
these, they make use of steps, as the young trees could not support
a ladder, and would besides be injured in their branches by the use
of one. The trees, with their foliage, are carefully watched, and the
mischiefs of insects prevented by the use of various applications,
among which are some essential oils.
The young trees of course suffer by being stripped of their leaves,
which are the _lungs_ of plants, and this is an additional reason for
renewing them after a certain time. They endeavor in part to counteract
the evil effect, by pruning and lopping the tree, so as to diminish the
wood when the leaves have been gathered. It is surprising, however, to
observe how soon a tree in those climates will recover its leaves in
the summer or autumn, after having been entirely stripped of them by a
typhoon or hurricane. Fresh plants are procured by cuttings or layers,
and sometimes from seed. When the trees grow too old for the production
of the finest leaves, and show a greater tendency to fruiting, they are
either removed or so cut and managed as to produce young branches.
The principal object, in the cultivation of the mulberry, is to produce
the greatest quantity of young and healthy leaves without fruit. For
this reason the trees are not allowed to exceed a certain age and
height. They are planted on the plan of a quincunx[136], and said to be
in perfection in about three years.
[136] In _gardening_, the _quincunx_ order is a plantation of trees
disposed in a square, consisting of five trees, one at each corner
and a fifth in the centre, which order repeated indefinitely,
forms a regular grove or wood, viewed by an angle of the square or
parallelogram, presents equal or parallel alleys.
Mr. Barrow, who observed the management of the trees and silk-worms
in Chĕ-kiang, confirms the usual Chinese accounts, by saying that
“the houses in which the worms are reared are placed generally in the
centre of each plantation, in order that they may be removed as far
as possible from every kind of noise; experience having taught them
that a sudden shout, or the bark of a dog, is destructive of the young
worms. A whole brood has sometimes perished from the effects of a
thunder-storm.”
Some notion of the extent of the care required in the management of the
worms may be formed from the following extract, taken from the Chinese
work referred to at the beginning of this chapter.
“The place where their habitation is built must be retired, free from
noise, smells, and disturbances of every kind. The least fright, makes
great impressions on these sensitive creatures; even the barking of
dogs, &c., is capable of throwing them into the utmost disorder.
For the purpose of paying them every attention an affectionate mother
is provided, who is careful to supply their wants; she is called
_Isan-mon_, ‘mother of the worms.’ She takes possession of the chamber,
but not before she has washed herself and put on clean clothes, which
have not the least repulsive smell; she must not have eaten anything
immediately before, or handled any wild succory, the smell of which is
very prejudicial. She must be clothed in a plain habit, without any
lining, that she may be more sensible of the warmth of the place, and
accordingly increase or lessen the fire. She must also carefully avoid
making a smoke or raising a dust, which would also be offensive.”
Silk-worms require to be carefully humored before the time of casting
their slough. Every day is to them a year, having in a manner, the four
seasons; the morning being the Spring; the middle of the day: Summer;
the evening: Autumn; and the night, Winter.
The chambers are so contrived as to admit of the use of artificial heat
when necessary. Great care is taken of the sheets of paper on which the
eggs have been laid; and the hatching is either retarded or advanced,
by the application of cold or heat according to circumstances, so as
to time the simultaneous exit of the young worms exactly to the period
when the tender spring-leaves of the mulberry are most fit for their
nourishment.
They proportion the food very exactly to the young worms by weighing
the leaves, which in the first instance are cut, but as the insects
become larger, are given to them whole. The greatest precautions being
observed in regulating the temperature of the apartments. The worms
are fed upon a species of small hurdles of basket-work, strewed with
leaves, which are constantly shifted for the sake of cleanliness, the
insects readily moving off to a fresh hurdle with new leaves, as the
scent attracts them. In proportion to their growth, room is afforded
to them by increasing the number of these hurdles, the worms of one
being shifted to three, then to six, and so on until they attain their
greatest size. When they have cast their several skins, reached their
greatest size, and assumed a transparent yellowish color, they are
removed to places divided into compartments, preparatory to casting
forth their silken filaments.
In the course of a week after the commencement of this operation, the
cocoons are complete, and it now becomes necessary to take them in
hand before the pupæ turn into _moths_, which would immediately bore
their way out, and spoil the cocoons. When a certain number, therefore,
have been laid aside for the sake of future eggs, the chrysalides are
killed by being placed in jars under layers of salt and leaves, with a
complete exclusion of air. They are subsequently placed in moderately
warm water, which dissolves the glutinous substance that binds the
silk together, and the filament is wound off upon reels. This is put
up in bundles of a certain size and weight, and either becomes an
article of merchandise under the name of “raw silk,” or is subjected
to the loom, and manufactured into various stuffs, for home or foreign
consumption. The Chinese notwithstanding the simplicity of their looms
(see frontispiece), will imitate _exactly_ the newest and most elegant
patterns from France. They particularly excel in the production of
_damasks_, _figured-satins_, and _embroidery_. Their crape has never
yet been perfectly imitated; and they make a species of washing silk,
called at Canton “ponge,” which, the longer it is used, the softer it
becomes.
The Chinese have from time immemorial been celebrated for the beauty of
their embroideries; indeed, it has been doubted whether the art was not
originally introduced into Europe by them, through the Persians.
From what has been said, it is evident that the raising of the
_mulberry-tree_ should first engage the attention of the cultivator,
since its leaves form the almost exclusive nourishment of the
silk-worm. It is scarcely necessary that we should in a work of this
description enter more fully into the cultivation of the mulberry-tree.
This has already been so ably done by Jonathan Cobb, Esq. of Dedham,
Mass., Dr. Pascalis of New York, Judge Comstock of Hartford, Conn., and
E. P. Roberts, Esq. of Baltimore, as to leave no stone unturned, or any
want upon the subject.
In such parts of the Chinese empire where the climate is favorable
to the practice, and where alone, most probably, the silk-worm is
indigenous, it remains at liberty, feeding on the leaves of its
native mulberry-tree, and going through all its mutations among the
branches, uncontrolled by the hand and unassisted by the cares of man.
As soon, however, as the silken balls have been constructed, they are
appropriated by the universal usurper, who spares only the few required
to reproduce their numbers, and thus furnish him with successive
harvests[137].
[137] Mons. Marteloy of Montpelier, who made many experiments upon
the rearing of silk-worms, presented a memorial upon the subject
to the French minister, in compliance with whose recommendation, a
few silk growers of Languedoc caused an experiment to be publicly
made in the open air, in the garden belonging to the Jesuits’
college at Montpelier. The whole was placed under the direction of
Mons. Marteloy, who had 1200 livres assigned to him to defray the
necessary expenses. The experiment succeeded perfectly. This was
in 1764. In the following year a second trial was made, and 1800
livres were set apart for the expenses. Owing, however, to the
unfavorable nature of the season, this experiment failed entirely,
the heavy and incessant rains making it impossible to keep the food
of the worms in a sufficiently dry state. The rearing of silk-worms
in the open air was not again attempted in that quarter; but the
partial success led to the adoption among cultivators of a better
system of ventilation, and the production of silk was about this
time very much extended throughout Languedoc.--_Obs. on the Culture
of Silk_, _by_ A. STEPHENSON.
This silk, the spontaneous offering of nature, is not, however,
equal in fineness to that produced by worms under shelter, and whose
progressions are influenced by careful management. Much attention
is, therefore, bestowed by the Chinese in the artificial rearing of
silk-worms. One of their principal cares, is to prevent the too early
hatching of the eggs, to which the nature of the climate so strongly
disposes them. The mode of insuring the requisite delay, is, to
cause the moth to deposit her eggs on large sheets of paper: these,
immediately upon their production, are suspended from a beam in the
room, while the windows are opened to expose them to the air. In a few
days the papers are taken down and rolled loosely up with the eggs
inside, in which form they are again hung during the remainder of the
summer and autumn. Towards the end of the year they are immersed in
cold water wherein a small portion of salt has been dissolved. In this
state the eggs are left during two days; and on being taken from the
salt and water are first hung to dry, and then rolled up rather more
tightly than before, each sheet of paper being thereafter inclosed in a
separate earthen vessel. Some persons, who are exceedingly particular
in their processes, use a lye made of mulberry-tree ashes, and place
the eggs likewise, during some minutes, on snow-water.
These processes appear efficacious for checking the hatching,
until the expanding leaves of the mulberry-tree give notice to the
silk-worm-rearer that he may take measures for bringing forth his
brood. For this purpose the rolls of paper are taken from the earthen
vessels, and hung up towards the sun, the side to which the eggs adhere
being turned from its rays, by being placed inside, and thus allowing
the heat to be transmitted to them through the paper. In the evening
the sheets are rolled closely up and placed in a warm situation.
The same proceeding is repeated on the following day, when the eggs
assume a grayish color. On the evening of the third day, after a
similar exposure, they are found to be of a much darker color, nearly
approaching to black; and the following morning, on the paper being
unrolled, they are covered with worms. In the higher latitudes the
Chinese have recourse to the heat of stoves, in order to promote the
simultaneous hatching of the eggs.
The apartments in which the worms are kept stand in dry situations, in
a pure atmosphere, and apart from all noise, which is thought to be
annoying to the worms, especially when they are young. The rooms are
made very close, but adequate means of ventilation provided: the doors
being open to the south. Each chamber is provided with nine or ten rows
of frames, placed one above the other. On these frames, rush hurdles
are ranged; upon which the worms are fed through their five ages. A
uniform degree of heat is constantly preserved, either by means of
stoves placed in the corners of the apartments, or by chafing-dishes
which from time to time are carried up and down the room. Flame and
smoke being always carefully avoided: cow-dung dried in the sun is
preferred by the Chinese to all other kinds of fuel for this purpose.
The most unremitting attention is paid to the wants of the worms,
which are fed night and day. On their being hatched they are furnished
with forty meals for the first day, thirty are given on the second
day, and fewer on and after the third. The Chinese believe that the
growth of silk-worms is accelerated, and their success promoted
by the abundance of their food, and therefore, in cloudy and damp
weather, when the insects are injuriously affected by the state of the
atmosphere, their appetites are stimulated by a wisp of very dry straw
being lighted and held over them, thus causing the cold and damp air to
be dissipated.
The Chinese calculate that the same number of insects which would, if
they had attained the full size in twenty-three or twenty-four days,
produce twenty-five ounces of silk, would give only twenty ounces if
their growth occupied twenty-eight days, and only ten ounces if forty
days. In order, therefore, to accelerate their growth, they supply
them with fresh food every half-hour during the first day of their
existence, and then gradually reduce the number of meals as the worms
grow older. It deserves to be remarked as a fact unnoticed in Natural
Theology, that the substance on which this valuable caterpillar feeds,
is the leaf of the mulberry-tree; and Providence, as if to ensure the
continuance of this useful species, has so ordained it that no other
insect will partake of the same food; thus ensuring a certain supply
for the little spinster.
Many persons believe that light is injurious to silk-worms; but, so far
from this opinion being correct, the opposite belief would probably
be nearer to the truth. In its native state, the insect is of course
exposed to light, and suffers no inconvenience on that account; and
it has been observed by one who gave much attention to the subject
(Count Dandolo), that in his establishment, “on the side on which the
sun shone directly on the hurdles, the silk-worms were stronger and
more numerous than in those places where the edge of the wicker hurdle
formed a shade.” The obscurity wherein the apartments are usually kept
has a very pernicious influence on the air: the food of the worms emits
in light oxygen, or vital air, while in darkness it exhales carbonic
acid gas, unfit for respiration. This well-known fact occurs alike
with all leaves similarly circumstanced[138]. To the bad effects thus
arising from the exclusion of the sun’s rays, another evil is added
by the nature of the artificial lights employed, being such as still
further to vitiate the air.
[138] “There is in the order of nature a certain, and very surprising
fact; when the leaves of vegetables are struck by the sun’s rays,
they exhale an immense quantity of vital air necessary to the life
of animals, and which they consume by respiration.
“These same leaves in the shade as well as in darkness exhale an
immense quantity of mephitic or fixed air, which cannot be inhaled
without destruction of life.
“This influence of the sun does not cease even when the leaf has
been recently gathered; on the contrary, in darkness, gathered
leaves will exhale a still greater quantity of mephitic air.
“Place one ounce of fresh mulberry leaves in a wide-necked bottle
of the size of a Paris pint, containing two pounds of liquid;
expose this bottle to the sun; about an hour afterwards, according
to the intensity of the sun, reverse the bottle and introduce a
lighted taper in it; this done, the light will become brighter,
whiter, and larger, which proves that the vital air contained in
the bottle has increased by that which has disengaged itself from
the leaves: to demonstrate this phenomenon more clearly, a taper
may be put in a similar bottle, that only contains the air which
has entered into it by its being uncorked. Shortly after the first
experiment, water will be found in the bottle which contained
the mulberry leaves; this water, evaporating from the leaves by
means of the heat, hangs on the sides, and runs to the bottom when
cooling; the leaves appear more or less withered and dry according
to the liquid they have lost. In another similar bottle place an
ounce of leaves, and cork it exactly like the former; place it
in obscurity, either in a box, or wrap it in cloths, in short,
so as totally to exclude light; about two hours after, open the
bottle, and put either a lighted taper or a small bird into it; the
candle will go out, and the bird will perish, as if they had been
plunged into water, which demonstrates that in darkness the leaves
have exhaled mephitic air, while in the sun they exhaled vital
air”.--COUNT DANDOLO’S _Treatise on the Art of Rearing Silk-worms_,
_p._ 144.
An almost incredible quantity of fluid is constantly disengaged by
evaporation from the bodies of the insects; and if means be not taken
to disperse this as it is produced, another cause of unwholesomeness
in the air arises. Noticing this, Count Dandolo observes, “This series
of causes of the deterioration of the air which the worms must inhale,
may be termed a continual conspiracy against their health and life;
and their resisting it, and living throughout shows them to have great
strength of constitution.”
In seven days from the commencement of the cocoons they are collected
in heaps; those which are designed to continue the breed being first
selected and set apart on hurdles, in a dry and airy situation. The
next care, is to destroy the vitality of the chrysalides in those balls
which are to be reeled. The most approved method of performing this,
is to fill large earthen vessels with cocoons, in layers, throwing in
one-fortieth part of their weight of salt upon each layer, covering the
whole with large dry leaves resembling those of the water-lilly, and
then closely stopping the mouths of the vessels. In reeling their silk
the Chinese separate the thick and dark from the long and glittering
white cocoons, as the produce of the former is inferior.
We are indebted to Dr. Ure for the two following articles (_extracted
from the Journal of the Asiatic Society, for January, 1837_), on wild
silk-worms. The first article is from the pen of Thomas Hugon, a
resident of Nowgong, and relates to wild silk-worms of Assam.
“The Assamese select for breeding, such cocoons only as have been
begun to be formed in the largest number on the same day, usually the
second or third after the commencement; those which contain males
being distinguishable by a more pointed end. They are put in a closed
basket suspended from the roof; the moths, as they come forth, having
room to move about, at the expiration of a day, the females (known
only by their large body) are taken out, and tied to small wisps of
thatching-straw, selected always from over the hearth, its darkened
color being thought more acceptable to the insect. If out of a batch,
there should be but few males; the wisps with the females tied to
them are exposed outside at night; and the males thrown away in the
neighborhood, find their way to them. These wisps are hung upon a
string tied across the roof, to keep them from vermin. The eggs laid
after the first three days, are said to produce weak worms. The wisps
are taken out morning and evening, and exposed to the sun, and in ten
days after being laid, a few of them are hatched. The wisps being then
hung up to the tree, the young worms find their way to the leaves. The
ant, whose bite is fatal to the worm in its early stages, is destroyed
by rubbing the trunk of the tree with molasses, and tying dead fish
and toads to it, to attract these rapacious insects in large numbers,
when they are destroyed with fire; a process which needs to be repeated
several times. The ground under the trees is also well cleared, to
render it easy to pick up and replace the worms which fall down. They
are prevented from coming to the ground, by tying fresh plantain-leaves
round the trunk, over whose slippery surface they cannot crawl; and
then transferred from exhausted trees to fresh ones, on bamboo platters
tied to long poles. The worms require to be constantly watched and
protected from the depredations of both day and night birds, as well
as rats and other vermin. During their moultings, they remain on
the branches; but when about beginning to spin, they come down the
trunk, and being stopped by the plantain-leaves, are there collected
in baskets, which are afterwards put under bunches of dry leaves,
suspended from the roof, into which the worms crawl, and form their
cocoons--several being clustered together: this accident, owing to the
practice of crowding the worms, which is most injudicious, rendering
it impossible to wind off their silk in continuous threads, as in the
filatures of Italy, France, and even Bengal. The silk is, therefore,
spun like flax, instead of being unwound in single filaments. After
four days the proper cocoons are selected for the next breed, and the
rest are reeled. The total duration of a breed varies from sixty to
seventy days; divided into the following periods:--
Four moultings, with one day’s illness attending each, 20
From fourth moulting to beginning of cocoon, 10
In the cocoon 20, as a moth 6, hatching of eggs 10, 36
--
66
“On being tapped with the finger, the body renders a hollow sound; the
quality of which shows whether they have come down for want of leaves
on the tree, or from their having ceased feeding.
“As the chrysalis is not soon killed by exposure to the sun, the
cocoons are put on stages, covered with leaves, and exposed to the hot
air from grass burned under them; they are next boiled for about an
hour in a solution of the potash, made from incinerated rice-stalks;
then taken out and put on a cloth folded over them to keep them warm.
The floss being removed by hand, they are then thrown into a basin of
hot water to be unwound; which is done in a very rude and wasteful way.
“The plantations for the mooga silk-worm in Lower Assam, amount to 5000
acres, besides what the forests contain; and yield 1500 maunds of 84
lbs. each per annum. Upper Assam is more productive.
“The cocoon of the _Koutkuri mooga_ is of the size of a fowl’s egg. It
is a wild species, and affords filaments much valued for fishing-lines.
“The _Arrindy_, or _Eria_ worm, and moth, is reared over a great part
of Hindostan, but entirely within doors. It is fed principally on
the _Hera_, or _Palma christi_ leaves, and gives sometimes 12 broods
of spun silk in the course of a year. It affords a fibre which looks
rough at first; but when woven, becomes soft and silky, after repeated
washings. The poorest people are clothed with stuff made of it, which
is so durable as to descend from mother to daughter. The cocoons are
put in a close basket, and hung up in the house, out of reach of rats
and insects. When the moths come forth, they are allowed to move about
in the basket for twenty-four hours; after which the females are tied
to long reeds or canes, twenty or twenty-five to each, and then hung
up in the house. Of the eggs that are laid the first three days, about
200, only are kept; then tied up for seed. When a few of the worms
are hatched, the cloths are put on small bamboo platters hung up in
the house, in which they are fed with tender leaves. After the second
moulting, they are removed to bunches of leaves suspended above the
ground, beneath which a mat is laid to receive them when they fall.
When they cease to feed, they are thrown into baskets full of dry
leaves, among which they form their cocoons, two or three being often
discovered joined together.
“The _Saturnia trifenestrata_ has a yellow cocoon of a remarkably
silky lustre. It lives on the soom-tree in Assam, but seems not to be
much used.”
The second article is from the pen of Dr. Helfer, upon those wild
silk-worms which are indigenous to India. Besides the _Bombyx
mori_, the Doctor enumerates the following seven species, formerly
unknown:--1. “The wild silk-worm of the central provinces, a moth not
larger than the _Bombyx mori_.” 2. “The Joree silk-worm of Assam,
_Bombyx religiosæ_, which spins a cocoon of a fine filament, with much
lustre. It lives upon the pipul tree (_Ficus religiosa_), which abounds
in India, and ought therefore to be turned to account in breeding this
valuable moth.” 3. “_Saturnia silhetica_, which inhabits the cassia
mountains in Silhet and Dacca, where its large cocoons are spun into
silk.” 4. “A still larger _Saturnia_, one of the greatest moths in
existence, measuring _ten inches_ from the _one end of the wing to the
other_[139]; observed by Mr. Grant, in _Chirra punjee_”. 5. “_Saturnia
paphia_, or the Tusseh silk-worm, is the most common of the native
species, and furnishes the cloth usually worn by Europeans in India.
It has not hitherto been domesticated, but millions of its cocoons are
annually collected in the jungles, and brought to the silk factories
near Calcutta and Bhagelpur. It feeds most commonly on the hair-tree
(_Zizyphus jujuba_), but it prefers the _Terminalia alata_, or Assam
tree, and the _Bombax heptaphyllum_. It is called _Koutkuri mooga_, in
Assam.” 6. “Another _Saturnia_, from the neighborhood of Comercolly.”
7. “_Saturnia assamensis_, with a cocoon of a yellow-brown color,
different from all others, called _mooga_, in Assam; which, although
it can be reared in houses, thrives best in the open air upon trees,
of which seven different kinds afford it food. The _Mazankoory mooga_,
which feeds on the Adakoory tree, produces a fine silk, which is nearly
white, and fetches 50 per cent. more than the fawn colored. The trees
of the first year’s growth produce by far the most valuable cocoons.
The mooga which inhabits the soom-tree, is found principally in the
forests of the plains, and in the villages. The tree grows to a large
size, and yields three crops of leaves in the year. The silk is of a
light fawn color, and ranks next in value to the Mazankoory. There are
generally five breeds of mooga worms in the year; 1. In January and
February; 2. In May and June; 3. In June and July; 4. In August and
September; 5. In October and November; the first and last being the
most valuable.”
[139] See p. 40. Also p. 54. footnote [63]
Dr. Anderson informs us, that in Madras the silk-worm goes through
all its evolutions in the short space of twenty-two days. It appears,
however, that the saving of time, and consequently labor, is the only
economy resulting from the acceleration; as the insects consume as
much food during their shorter period of life, as is assigned to the
longer-lived silk-worms of Europe.
We extract the following paper, with slight emendations, from
Ellsworth’s Report of the Patent Office for the year 1844, being a
communication from Dr. Stebbins of Northampton, Mass[140]., to the
Editor of the American Agriculturalist, as having some bearing upon the
present subject.
[140] See Chapter XIII. p. 211.
“As requested, I forward you a sketch of Mr. Gill’s cradle for feeding
silk-worms, (It is not necessary for us to give a drawing of it in
a work like the present, which is chiefly intended for the general
reader, and besides, this machine is already sufficiently known to
silk culturists.) I have five patches of mulberry, (in all, ten or
twelve acres,) two parcels of which you have seen. The one adjoining my
garden, by estimation, may furnish foliage sufficient for a million and
a half of worms. The mulberries consist of the white, black, alpine,
broosa, moretta, alata, multicaulis, Asiatic, and large-leaf Canton.
The two latter I prefer for my own use--the Canton for early feeding
with foliage, and the Asiastic for branch feeding. The Canton is highly
approved of for producing heavy and firm cocoons, which, by competent
testimony and experiments, have been found in favor of the Canton feed
as five to eight, and is the true species used by the Chinese, as
testified by a resident Missionary, the Rev. E. C. Bridgman, and more
recently by Dr. Parker, while on his late visit to the United States.
I consider the peanut variety of worms the best for producing the most
silk of a good quality.
“From an elevated plat near my cocoonery, you had a view of our
extensive meadows spread out at the foot of Mount Holyoke. My cocoonery
you have examined, with its fixtures for feeding silk-worms--the mode
of open feeding, ventilator, and ventilating cradles. Since you left,
the whole has been completed, with hammocks suspended over the cradles,
easily put in motion, and so constructed that no offal can drop into
the cradles beneath, nor interfere with the rocking motion or winding;
the arrangement is much admired, and estimated to accommodate half a
million of worms, or more, to be fed simultaneously. About half of
the cocoonery has hurdles of lattice work, covered in part with gauze
netting four feet wide and the same number of tiers in height. The
cocoonery is supposed to be sufficiently open on the sides, ends, and
roof, to admit a free circulation of pure air. The flooring is the
natural earth.
“The past winter has been uncommonly severe on grape-vines and fruit;
forest and mulberry trees; the Asiatic I found the most hardy of any
other, and the Canton the earliest in foliage. On the 21st and 22d
of May there were severe frosts, destroying garden vegetables, and
injuring some early mulberry foliage; added to this, ice was formed
in many places. The accounts from Vermont and New Hampshire are so
disastrous as to delay early feeding; while in Northampton, June 14, at
one of my plantations, you saw silk-worms in the act of winding, and
others in a good state of forwardness. On the day of your departure,
I received a letter from a distant silk grower, a staunch promoter
of the _one early_ and _open_ crop system, that, on account of the
unpropitious season and condition of his trees, he would delay fetching
out his worms until the last of June, and then make his great effort
upon one crop.
“To provide against premature hatching of silk-worms, or the disaster
of an early frost, it is advisable to have foliage gathered and dried
the year preceding; which, being pulverized and moistened with water,
may be given to the worms until new foliage appears; and they will eat
it freely.
“To obtain the most and best foliage of the mulberry, it will be
necessary every Spring to cut or head them down within three or four
inches of the ground, and preserve the stalks for _bark-silk_. I have
a quantity of them saved with bark peeled from the large Asiatics
to be used for making _bark-silk_, in addition to a quantity of
mulberry-leaves preserved for making paper. The whole process, although
not carried out, as yet, in this country, with either, has been
successfully accomplished in France, from proof shown by M. Frassinet.
I am endeavoring to have it tested here, by subjecting both stalk
and peeled bark to the operation of steaming with soap and water, to
facilitate the separation of the bark from the wood, and the outside
cuticle from the fibrous substance of the bark, before trying the
operation of the brake for dressing, carding, spinning, &c. Should it
prove successful, it will be made public (See Mr. Zinke’s process,
Chapter XI.). Hopes are entertained that what has been done may be done
again; that Yankee ingenuity and perseverance may prove a match for
foreign cheap labor(?).
“The present time has been called the age of invention and improvement.
But if ”there is nothing new under the sun” (a pretty fair illustration
of this assertion of the wise man--Vide Ecclesiastes i. 9, 10.--will be
found in this work.); and if what is, has been and may be again, then
may we hope to be benefitted by the reproduction of astonishing results
in all coming time; and even now, while there has been anxious inquiry
for some easy mode to separate the bark of the mulberry from the wood,
an _historical fact_ has been recently communicated(?); by which,
some two hundred and forty years ago, in the year 1600, an accident
occurred, which resulted in the manufacture of a handsome fabric from
the fibrous bark of the mulberry, with the inference that the bark had
been previously used for the manufacture of cordage, on account of the
superior strength of the fibrous bark over that of other materials used
for cordage[141].
“Under date of June 6, 1844, I have been favored with a letter from
the president of one of the most eminent literary institutions of our
country, who expresses his opinion of the progress of silk culture as
follows:
‘I am gratified to find a renewed and more general interest excited
at the present time. If this awaking up to a scientific and practical
consideration of the subject is not soon crowned with signal success,
I am satisfied it will not be for want of enterprize or skill in our
countrymen, but merely from the high price of labor, compared with
the scanty wages given in other silk-growing countries. Even this
consideration (though it may retard for a while the complete success
of this department of productive industry), will not prevent its
ultimate triumph.’
“The above is the opinion of one of the most scientific men of the age,
who, in early life, was himself a silk grower. His opinion accords with
that of many others of high consideration in the United States.
“While viewing the flourishing condition of one of my mulberry patches,
you asked with what it had been manured? and received for answer,
_ashes_, and the _deciduous foliage_. The foliage, you thought, could
be gathered for making _paper_, and answered, that there would be
sufficient defective foliage left to manure the land; the foliage
is richer than any stable manure, and stable manure should never be
applied to the mulberry. I have not had occasion the last five or six
years to use even ashes as a manure, but keep the land in good tilth
by frequent hoeing. If you found these mulberries more flourishing
than others you had seen, it may be attributed, in a great measure, to
frequent hoeing, and dressing with the decayed mulberry foliage.
“The soil is a light sandy loam; and, previous to its being stocked
with mulberry, would not yield the value of $10 in any crop; and now,
my feeder says, if his worms do well, he hopes to get $800 for the
crop! A part of this lot being stocked with alpine, broosa, and Asiatic
mulberry, of 6 to 10 feet in height, in rows 3 feet apart; and having
grown so vigorously as to shade each other, and liable to have spotted
leaves. I have, in order to avoid this, and procure more, larger,
and better foliage, cut away or headed down every other row, within
three or four inches of the ground; and from the stumps have sprung
up a multitude of thrifty sprouts, now fit for use, and the leaves
three times larger than those on the standard trees, are so fresh and
tender, that in some measure it is hoped, they may answer the purpose
of seedling foliage, so highly recommended by M. Frassinet, who has
the following encomium on _seedling_ foliage: ‘that 100 pounds of
such foliage is worth near 200 pounds of old leaves to make the same
quantity of cocoons; or in fact, equivalent in value to nearly double
the stock of other foliage.’ I have caused considerable bark to be
stripped from the Asiatic trees cut away for manufacturing purposes;
and M. Rouviere, of Lyons, has proved that the bark of young shoots,
submitted to the same process as hemp, yields abundant silk-fibre
to make beautiful tissues (noticed at the close of Chapter XI.). I
should advise silk growers to preserve the shoots, have them barked in
the best way, and the silky fibre rotted, carded, spun, and wove. M.
Rouviere asserts that it will be not only fine and strong, but take
the most beautiful colors. Of the bark, ropes and nets are made in the
Morea, and may be applied to great advantage in the manufacture of
paper, together with the foliage.
“The Canton and Asiatic seed sown this year are in a flourishing
condition for plantation use, exclusive of several mulberry plantations
which will be for rent, or growing silk on shares, next spring. Up to
the first of July, worms have been uncommonly healthy--the probable
effect of more open ventilation than in former years.
“Mr. Dabney, consul at Fayal, (now in Boston) has two millions of worms
at present on feed. S. Whitmarsh, at Jamaica, has 360 of what he calls
_creolized native_ eggs, in constant feed, which go through the whole
course to the cocoon in 24 days. The eggs hatch in 10 days after being
laid. He has received the silk report, and made such improvement as to
save, in all, nine-tenths of the usual labor. The silk cause at Jamaica
occasions great interest in England for its prosperity and success.”
D. Stebbins.
Northampton, Mass., _July_, 1844.
[141] We have abundant testimony that the most beautiful fabrics,
comprising _mantles_, &c., as well as cordage, was produced from
the bark of trees, as early as the year 412 B. C. So that Mr.
Stebbins’s “_historical fact_” is anticipated by 2012 years! (See
Chapters XII. and XIII. of this Part.)
We will now conclude this Chapter with Dr. Bowling’s admirable
illustration, of the mutual dependence of the arts upon each other:--
“Let us fancy that some thousand years ago, a mortal, wandering
through an oriental wood, saw a worm falling from a fruit-bearing
tree--that he found this little creature had reached the end of one
of its stages of existence, and was laboriously engaged in shrouding
itself in an unknown substance, like a fine thread of gold, out of
which it constructed its tomb; that, attracted by the circumstance,
he found this shroud to consist of a thread hundreds of yards long,
which a very little attention enabled him to detach; he found he
could strengthen the threads by uniting them together, and they
could be applied to various purposes of usefulness; he thought of
winding off the thread; the reel lends him the first assistance,
but he could not make the reel without the co-operation of a knife,
or some such instrument with a sharp edge. Thus the aid of art--of
the produce of art--is already called in. With this rude instrument
he makes a machine which enables him to reel off the thread coffin
of the curious animal. In process of time, he finds that this fine
filament can be applied to the making of garments--garments alike
useful and ornamental. Now trace the progress of things by which,
from the narrow sphere of his observation and experiment, his
success spreads through the districts he inhabits, and from them
to other lands, and becomes an object of importance to communicate
with the whole family of man. By and by the cocoon, or its produce,
finds its way to foreign countries, probably more enlightened than
his own, again to be operated on by a higher intelligence and more
practised skill. This associates the thread of the silk-worm with a
ship, with ship-building, and all its marvellous combinations.--Some
wandering merchant probably conveyed the raw material to Persia; some
adventurous mariner to Greece or Italy, or other regions where it gave
a new impulse to science and to thought. But consider for a moment,
before the ship was launched upon the water, how many elements were
necessary for its production; think of how multitudinous and various
the materials which that ship required for its construction, before
the products of that remote country are brought to their ultimate
markets for manufacture. I refer to this particular topic, because
it is associated with the prosperity of the districts in which we
are, and I wished to carry back your thoughts to the germ whence
that prosperity sprung.”--BOWRING’S _Lecture at the Poplar
Institution_.
CHAPTER IX.
THE SPIDER.
ATTEMPTS TO PROCURE SILKEN FILAMENTS FROM SPIDERS.
Structures of spiders--Spiders not properly insects, and
why--Apparatus for spinning--Extraordinary number of
spinnerules--Great number of filaments composing one thread--Réaumur
and Leeuwenhoeck’s laughable estimates--Attachment of the thread
against a wall or stick--Shooting of the lines of spiders--1.
Opinions of Redi, Swammerdam, and Kirby--2. Lister, Kirby, and
White--3. La Pluche and Bingley--4. D’Isjonval, Murray, and
Bowman--5. Experiments of Mr. Blackwall--His account of the
ascent of gossamer--6. Experiments by Rennie--Thread supposed
to go off double--Subsequent experiments--Nests, Webs, and Nets
of Spiders--Elastic satin nest of a spider--Evelyn’s account of
hunting spiders--Labyrinthic spider’s nest--Erroneous account
of the House Spider--Geometric Spiders--Attempts to procure
silken filaments from Spiders bags--Experiments of M. Bon--Silken
material--Manner of its preparations--M. Bon’s enthusiasm--His
spider establishment--Spider-silk not poisonous--Its usefulness
in healing wounds--Investigation of M. Bon’s establishment by M.
Réaumur--His objections--Swift’s satire against speculators and
projectors--Ewbank’s interesting observations on the ingenuity of
spiders--Mason-spiders--Ingenious door with a hinge--Nest from
the West Indies with spring hinge--Raft-building Spider--Diving
Water-Spider--Rev. Mr. Kirby’s beautiful description of
it--Observations of M. Clerck--Cleanliness of Spiders--Structure of
their claws--Fanciful account of them patting their webs--Proceedings
of a spider in a steamboat--Addison--His suggestions on the
compilation of a “History of Insects.”
Of spiders there are many species; most of them extend their labors no
farther than merely to make a web to ensnare and detain their food. But
others are known to go beyond this, and spin a bag in the form of a
cocoon, for the protection of their eggs, nearly similar to that of the
silk-worm.[142]
[142] Don Luis Nee observed on certain trees growing in Chilpancingo,
Tixtala in South America, ovate nests of caterpillars, eight
inches long, which the inhabitants manufacture into stockings and
handkerchiefs.--Annals of Botany, 2d, p. 104.
Modern naturalists do not rank spiders among insects, because they
have no antennæ, and no division between the head and shoulders. They
breathe by leaf-shaped gills, situated under the belly, instead of
spiracles in the sides; and have a heart connected with these. But as
spiders are popularly considered insects, it will sufficiently suit our
purpose to introduce them here as such.
Spiders are usually classed according to their difference of color,
whether black, brown, yellow, &c., or sometimes by the number and
arrangement of their eyes: of these organs some possess no fewer than
ten, others eight, and others again six[143].
[143] Porter’s “Treatise on the Silk Manufacture,” p. 168.
Some species of spiders are known to possess the power of not merely
forming a web, but also of spinning, for the protection of their
eggs, a bag somewhat similar in form and substance to the cocoon of
the silk-worm. The apparatus by which they construct their ingenious
fabrics, is much more complicated than that which is common to the
various species of caterpillars. Caterpillars have only two reservoirs
for the materials of their silk; but the spider spins minute fibres
from fine papillæ, or small nipples placed in the hinder part of its
body. These papillæ serve the office of so many wire-drawing machines,
from which the silken threadlets are ejected. Spiders, according to the
dissections of M. Treviranus, have four principal vessels, two larger
and two smaller, with a number of minute ones at their base. Several
small tubes branch towards the reservoirs, for carrying to them, no
doubt, a supply of the secreted material. Swammerdam describes them as
twisted into many coils of an agate color[144]. We do not find them
coiled, but nearly straight, and of a deep yellow color. From these,
when broken, threads can be drawn out like those spun by the spider,
though we cannot draw them so fine by many degrees.
[144] Hill’s Swammerdam, part i. p. 23.
From these little flasks or bags of gum, situated near the apex of the
abdomen, and not at the mouth as in caterpillars, a tube originates,
and terminates in the external spinnerets, which may be seen by the
naked eye in the form of five little teats surrounded by a small
circle, as represented in Fig. 8. Plate IV.; this figure shows the
garden spider (_Epeira diadema_) suspended by a thread proceeding from
its spinneret.
We have seen that the thread of the silk-worm is composed of two
filaments united, but the spider’s thread would appear, from the first
view of its five spinnerets, to be quintuple, and in some species
which have six teats, so many times more. It is not safe, however,
in our interpretations of nature to proceed upon conjecture, however
plausible, nor to take anything for granted which we have not actually
seen; since our inferences in such cases are almost certain to be
erroneous. If Aristotle, for example, had ever looked narrowly at a
spider when spinning, he could not have fancied, as he does, that the
materials which it uses are nothing but wool stripped from its body.
On looking, then, with a strong magnifying glass, at the teat-shaped
spinnerets of a spider, we perceive them studded with regular rows
of minute bristle-like points, about a thousand to each teat, making
in all from five to six thousand. These are minute tubes which we
may appropriately term _spinnerules_, as each is connected with the
internal reservoirs, and emits a thread of inconceivable fineness. Fig.
9. represents this wonderful apparatus as it appears in the microscope.
We do not recollect that naturalists have ventured to assign any cause
for this very remarkable multiplicity of the spinnerules of spiders,
so different from the simple spinneret of caterpillars. To us it
appears an admirable provision for their mode of life. Caterpillars
neither require such strong materials, nor that their thread should
dry as quickly. It is well known in our manufactures, particularly
in rope-spinning, that in cords of equal thickness, those which are
composed of many smaller ones united are stronger than those spun at
once. In the instance of the spider’s thread, this principle must
hold still more strikingly, inasmuch as it is composed of fluid
materials that require to be dried rapidly, and this drying must be
greatly facilitated by exposing so many to the air separately before
their union, which is effected at about the tenth of an inch from
the spinnerets. In Fig. 10. Plate IV. each of the threads shown is
represented to contain one hundred minute threads, the whole forming
only one of the spider’s common threads. In the figure the threads are,
of course, greatly magnified, so that, for the small space represented,
the lines are shown as parallel. The threadlets, or filaments as they
come from the papillæ, are too fine to be counted with any degree of
accuracy, but it is evident that very many are sent forth from each
of the larger papillæ. This fact tends to explain the power possessed
by the spider of producing threads having different degrees of
tenuity. By applying more or less of these papillæ against the place
whence it begins its web, the spider joins into one thread the almost
imperceptible individual filaments which it draws from its body; the
size of this thread being dependent on the number of nipples employed,
and regulated by that instinct which teaches the creature to make
choice of the degree of exility most appropriate to the work wherein it
is about to engage.
Réaumur relates that he has often counted as many as seventy or
eighty fibres through a microscope, and perceived that there were yet
infinitely more than he could reckon; so that he believed himself to be
far within the limit of truth in computing that the tip of _each_ of
the five papillæ furnished 1000 separate fibres: thus supposing that
one slender filament of a spider’s web is made up of 5000 fibres!
Leeuwenhoeck, in one of his extraordinary microscopical observations
on a young spider, not bigger than a grain of sand, upon enumerating
the threadlets in one of its threads, calculated that it would require
_four millions_ of them to be as thick as a hair of his head!
Another important advantage derived by the spider from the
multiplicity of its threadlets is, that the thread affords a much more
secure attachment to a wall, a branch of a tree, or any other object,
than if it were simple; for, upon pressing the spinneret against the
object, as spiders always do when they fix a thread, the spinnerules
are extended over an area of some diameter, from every hair’s breadth
of which a strand, as rope-makers term it, is extended to compound
the main cord. Fig. 11. Plate IV. exhibits, magnified, this ingenious
contrivance. Those who may be curious to examine it, will see it best
when the line is attached to any black object, for the threads, being
whitish, are, in otherwise, not so easily perceived.
SHOOTING OF THE LINES.--It has long been considered a curious
though difficult investigation, to determine in what manner spiders,
seeing that they are destitute of wings, transport themselves from tree
to tree, across brooks, and frequently through the air itself, without
any apparent starting point. On looking into the authors who have
treated upon this subject, it is surprising how little there is to be
met with that is new, even in the most recent. Their conclusions, or
rather their conjectural opinions, are, however, worthy of notice; _for
by unlearning error, we the more firmly establish truth_.
1. One of the earliest notions upon this subject is that of Blancanus,
the commentator on Aristotle, which is partly adopted by Redi, by
Henricus Regius of Utrecht, by Swammerdam[145], by Lehmann, as well as
by Kirby and Spence[146]. “The spider’s thread,” says Swammerdam, “is
generally made up of two or more parts, and after descending by such a
thread, it ascends by one only, and is thus enabled to waft itself from
one height or tree to another, even across running waters; the thread
it leaves loose behind it being driven about by the wind, and so fixed
to some other body.” “I placed,” says Kirby, “the large garden spider
(_Epeira diadema_) upon a stick about a foot long, set upright in a
vessel containing water.... It let itself drop, not by a single thread,
but by _two_, each distant from the other about the twelfth of an inch,
guided, as usual, by one of its hind feet, and that one apparently
smaller than the other. When it had suffered itself to descend nearly
to the surface of the water, it stopped short, and by some means, which
I could not distinctly see, broke off, close to the spinners, the
smallest thread, which still adhering by the other end to the top of
the stick, floated in the air, and was so light as to be carried about
by the slightest breath. On approaching a pencil to the loose end of
this line, it did not adhere from mere contact. I, therefore, twisted
it once or twice round the pencil, and then drew it tight. The spider,
which had previously climbed to the top of the stick, immediately
pulled at it with one of its feet, and finding it sufficiently tense,
crept along it, strengthening it as it proceeded by another thread, and
thus reached the pencil.”
[145] Swammerdam, part i. p. 24.
[146] Intr. vol. i. p. 415.
1. “We have repeatedly witnessed this occurrence,” says Mr. Rennie,
“in the fields, and when spiders were placed for experiment, as Kirby
has described; but we very much doubt that the thread broken is ever
intended as a bridge cable, or that it would have been so used in that
instance, had it not been artificially fixed and again accidentally
found by the spider. According to our observations, a spider never for
an instant, abandons, the thread which she dispatches in quest of an
attachment, but uniformly keeps trying it with her feet, in order to
ascertain its success. We are, therefore, persuaded, that when a thread
is broken in the manner above described, it is because it has been spun
too weak, and spiders may often be seen breaking such threads in the
process of netting their webs.”
The plan, besides, as explained by these distinguished writers, would
more frequently prove abortive than successful, from the cut thread
not being sufficiently long. They admit, indeed, that spiders’ lines
are often found “a yard or two long, fastened to twigs of grass not a
foot in height.... Here, therefore, some other process must have been
used[147].”
[147] Kirby and Spence, vol. i. Intr. p. 416.
2. The celebrated English naturalist, Dr. Lister, whose treatise
upon the native spiders of that country, has been the basis of every
subsequent work on the subject, maintains that “some spiders shoot out
their threads in the same manner that porcupines do their quills[148];
that whereas the quills of the latter are entirely separated from
their bodies, when thus shot out, the threads of the former remain
fixed to their anus, as the sun’s rays to its body[149].” A French
periodical writer goes a little farther, and says, that spiders have
the power of shooting out threads, _and directing them at pleasure
towards a determined point_, judging of the distance and position
of the object by some sense of which we are ignorant[150]. Kirby
also says, that he once observed a small garden spider (_Aranea
reticulata_) “standing midway on a long perpendicular fixed thread, and
an appearance caught” his “eye, of what seemed to be the emission of
threads.” “I,” therefore, he adds, “moved my arm in the direction in
which they apparently proceeded, and, as I had suspected, a floating
thread attached itself to my coat, along which the spider crept. As
this was connected with the spinners of the spider, it could not have
been formed” by breaking a “secondary thread[151].” Again, in speaking
of the gossamer-spider, he says, “it first extends its thigh, shank,
and foot, into a right line, and then, elevating its abdomen till it
becomes vertical, _shoots its thread_ into the air, and flies off from
its station[152].”
[148] Porcupines do not shoot out their quills, as was once generally
believed.
[149] Lister, Hist. Animalia Angliæ, 4to. p. 7.
[150] Phil. Mag. ii. p. 275.
[151] Vol. i. Intr. p. 417.
[152] Ibid. ii. p. 339.
Another distinguished naturalist, Mr. White of Selborne, in speaking
of the gossamer-spider, says, “Every day in fine weather in autumn do
I see these spiders shooting out their webs, and mounting aloft: they
will go off from the finger, if you take them into your hand. Last
summer, one alighted on my book as I was reading in the parlor; ran
to the top of the page, and _shooting out a web_, took its departure
from thence. But what I most wondered at, was, that it went off with
considerable velocity in a place where no air was stirring; and I am
sure I did not assist it with my breath[153].”
[153] Nat. Hist. of Selborne, vol. i. p. 327.
“Having so often witnessed,” says Mr. Rennie, “the thread set afloat
in the air by spiders, we can readily conceive the way in which
those eminent naturalists were led to suppose it to be ejected by
some animal force acting like a syringe; but as the statement can be
completely disproved by experiment, we shall only at present ask, in
the words of Swammerdam--‘how can it be possible that a thread so fine
and slender should be shot out with force enough to divide and pass
through the air?--is it not rather probable that the air would stop
its progress, and so entangle it and fit it to perplex the spider’s
operations[154]?’” The opinion, indeed, is equally improbable with
another suggested by Dr. Lister, that the spider can retract her thread
within the abdomen, after it has been emitted[155]. De Geer[156] very
justly joins Swammerdam in rejecting both of these fancies, which,
in our own earlier observations upon spiders, certainly struck us as
plausible and true. There can be no doubt, indeed, that the animal has
a voluntary power of permitting the material to escape, or stopping it
at pleasure, but this is not projectile.
[154] Book of Nature, part i. p. 25.
[155] Hist. Anim. Anglæ, 4to.
[156] Mémoires, vol. vii. p. 189.
3. “There are many people,” says the Abbé de la Pluche, “who believe
that the spider flies when they see her pass from branch to branch,
and even from one high tree to another; but she transports herself
in this manner; and places herself upon the end of a branch, or some
projecting body, and there fastens her thread; after which, with her
two hind feet, she squeezes her dugs (_spinnerets_), and presses out
one or more threads of two or three ells in length, which she leaves
to float in the air till it be fixed to some particular place[157].”
Without pretending to have observed this, Swammerdam says, “I can
easily comprehend how spiders, without giving themselves any motion,
may, by only compressing their spinnerets, force out a thread, which
being driven by the wind, may serve to waft them from place to
place[158].” Others, proceeding upon a similar notion, give a rather
different account of the matter. “The spider,” says Bingley, “fixes one
end of a thread to the place where she stands, and then with her hind
paws _draws out_ several other threads from the nipples, which, being
lengthened out and driven by the wind to some neighboring tree or other
object, are by their natural clamminess fixed to it[159].”
[157] Spectacle de la Nature, vol. i.
[158] Book of Nature, pt. i. p. 25.
[159] Animal Biography, vol. iii. p. 475, 3d edition.
Observation gives some plausibility to the latter opinion, as the
spider always actively uses her legs, though not to draw out the
thread, but ascertain whether it has caught upon any object. The notion
of her pressing the spinneret with her feet must be a mere fancy; at
least it is not countenanced by anything which we have observed.
4. An opinion much more recondite is mentioned, if it was not started,
by M. D’Isjonval, that the floating of the spider’s thread is
electrical. “Frogs, cats, and other animals,” he says, “are affected
by natural electricity, and feel the change of weather; but no other
animal more than myself and spiders.” In wet and windy weather he
accordingly found that they spun very short lines, “_but when a spider
spins a long thread, there is a certainty of fine weather for at least
ten or twelve days afterwards_[160].” A periodical writer, who signs
himself Carolan[161], fancies that in darting out her thread the spider
emits a stream of air, or some subtle electric fluid, by which she
guides it as if by magic.
[160] Brez, Flore des Insectophiles. Notes, Supp. p. 134.
[161] Thomson’s Ann. of Philosophy, vol. iii. p. 306.
A living writer (Mr. John Murray) whose learning and skill in
conducting experiments give no little weight to his opinions, has
carried these views considerably farther. “The aëronautic spider,” he
says, “can propel its thread both horizontally and vertically, and at
all relative angles, _in motionless air_ and in an _atmosphere agitated
by winds_; nay more, the aërial traveller can even dart its thread, to
use a nautical phrase, in the ‘wind’s eye.’ My opinion and observations
are based on many hundred experiments.... The entire phenomena are
electrical. When a thread is propelled in a vertical plane, it remains
perpendicular to the horizontal plane always upright, and when others
are projected at angles more or less inclined, their direction is
invariably preserved; the threads never intermingle, and when a pencil
of threads is propelled, it ever presents the appearance of a divergent
brush. These are electrical phenomena, and cannot be explained but on
electrical principles.”
“In clear, fine weather, the air is invariably positive; and it is
precisely in such weather that the aëronautic spider makes its ascent
most easily and rapidly, whether it be in summer or winter.” “When the
air is weakly positive, the ascent of the spider will be difficult, and
its altitude extremely limited, and the threads propelled will be but
little elevated above the horizontal plane. When negative electricity
prevails, as in cloudy weather, or on the approach of rain, and the
index of De Saussure’s hygrometer rapidly advancing towards humidity,
the spider is unable to ascend[162].”
[162] Loudon’s Mag. of Nat. Hist., vol. i. p. 322.
Mr. Murray tells us, that “when a stick of excited sealing-wax is
brought near the thread of suspension, it is evidently repelled;
consequently, the electricity of the thread is of a negative
character,” while “an excited glass tube brought near, seemed to
attract the thread, and with it the aëronautic spider[163].” His
friend, Mr. Bowman, further describes the aërial spider as “shooting
out four or five, often six or eight, extremely fine webs several
yards long, which waved in the breeze, diverging from each other like
a pencil of rays.” One of them “had two distinct and widely diverging
fasciculi of webs,” and “a line uniting them would have been at right
angles to the direction of the breeze[164].”
[163] Experim. Researches in Nat. Hist., p. 136.
[164] Mag. Nat. Hist. vol. i. p. 324.
“Such is the chief evidence in support of the electrical theory,” says
Mr. Rennie; “but though we have tried these experiments, we have not
succeeded in verifying any one of them. The following statements of Mr.
Blackwall come nearer our own observations.
5. ‘Having procured a small branched twig,’ says Mr. Blackwall, ‘I
fixed it upright in an earthen vessel containing water, its base being
immersed in the liquid, and upon it I placed several of the spiders
which produce gossamer. Whenever the insects thus circumstanced were
exposed to a current of air, either naturally or artificially produced,
they directly turned the thorax towards the quarter whence it came,
even when it was so slight as scarcely to be perceptible, and elevating
the abdomen, they emitted from their spinners a small portion of
glutinous matter, which was instantly carried out in a line, consisting
of four finer ones, with a velocity equal, or nearly so, to that with
which the air moved, as was apparent from observations made on the
motion of detached lines similarly exposed. The spiders, in the next
place, carefully ascertained whether their lines had become firmly
attached to any object or not, by pulling at them with the front pair
of legs; and if the result was satisfactory, after tightening them
sufficiently, they made them pass to the twig; then discharging from
their spinners, which they applied to the spot where they stood, a
little more of their liquid gum, and committing themselves to these
bridges of their own constructing, they passed over them in safety,
drawing a second line after them, as a security in case the first gave
way, and so effected their escape.
‘Such was invariably the result when spiders were placed where the air
was liable to be sensibly agitated: I resolved, therefore, to put a
bell-glass over them; and in this situation they remained seventeen
days, evidently unable to produce a single line by which they could
quit the branch they occupied, without encountering the water at its
base; though, on the removal of the glass, they regained their liberty
with as much celerity as in the instances already recorded.
‘This experiment, which, from want of due precaution, has misled so
many distinguished naturalists, I have tried with several geometric
spiders, and always with the same success[165].’”
[165] Linn. Trans., vol. xv. p. 456.
Mr. Blackwall, from subsequent experiments, says he is “confident
in affirming, that in motionless air, spiders have not the power of
darting their threads even through the space of half an inch[166].”
The following details are given in confirmation of this opinion. Mr.
Blackwall observed, the 1st of Oct., 1826, a little before noon, with
the sun shining brightly, no wind stirring, and the thermometer in the
shade ranging from 55°.5 to 64°, a profusion of shining lines crossing
each other at every angle, forming a confused net-work, covering the
fields and hedges, and thickly coating his feet and ankles, as he
walked across a pasture. He was more struck with the phenomenon because
on the previous day a strong gale of wind had blown from the south,
and as gossamer is only seen in calm weather, it must have been all
produced within a very short time.
[166] Mag. Nat. Hist., vol. ii. p. 397.
“What more particularly arrested my attention,” says Mr. Blackwall,
“_was the ascent of an amazing quantity of webs of an irregular,
complicated structure, resembling ravelled silk of the finest quality,
and clearest white; they were of various shapes and dimensions, some of
the largest measuring upwards of a yard in length, and several inches
in breadth in the widest part; while others were almost as broad as
long, presenting an area of a few square inches only_.