Francis Lieber.

Library of universal knowledge. A reprint of the last (1880) Edinburgh and London edition of Chambers' encyclopaedia, with copious additions by American editors (Volume 13) online

. (page 164 of 203)
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then, that a ship is in lat.
50 n., long. 20 3 w., and is
bound for a point in lat. 10*
n. and long. 80 w., and
that its great circle track,
etc., are required: let P, the
pole of the under circle,
represent the place of the
ship (the circle ZI J D always
representing the meridian of
the point of departure, and
the uppercircle, whose pole
is Z, representing the earth's
hemisphere), which is done
by turning the upper circle
till P appears at lat. 50




Pio.1.



X represents the point to be arrived at, and consequently PX, the arc of a great circle
passing through P and X, is the great circle track, PD is the difference of latitude. EP
the difference of longitude; the spherical angle XPD, measured by Gil, an arc of a
great circle, of which P is the pole, is the course; and the length of PX is measured by
PT, the portion of PS which is cut off by a parallel of the under circle through X, in
degrees. The data, then, being as above, we find by inspection of the instrument the
difference of lat. = 40 s., the difference of long. = 60 w., the course = s. 7 w.,
and the distance = 63J= 3,800 nautical miles. Besides the saving of time and labor
by the use of this instrument the whole work being the setting of the instrument, and
then the reading off of the required elements it is evident that the substitution of a
mechanical solution for calculation greatly lessens the probability of error. It is found
that spherographs of 5 in. radius give results of sufficient accuracy for all the purpose*
of the navigator.

All other spherical problems can be
solved with equal facility by this instru-
ment, but one more example will suffice.
Let Z (fij* 2) now represent the zenith of
a place, ZHNR its meridian, P the north
pole of the heavens; the other lines are
then circles of declination, altitude, azi-
muth, and hour circles; and let O repre-
sent the place of the sun in given declina-
tion and altitude at a certain time. The
instrument is now set by turning round
the upper card till the point O (determined
by its circle of declination and hour circle)
on the under card falls upon the circle of
given altitude on the upper card, then d is
the sun's place at noon, Hd being his
meridian altitude, PR the latitude of the
place, the angle RPS (measured in degrees
along QE) the time of sunset, ds half the
length of the day, sc half the length of the
night, etc. The spherograph is also use-
ful in finding latitude when the horizon is
hid by fogs, right ascensions at night, and

in correcting lunar observations; but for these purposes, spherographs are specially
constructed, as some slight variations in the form given above are necessary.




Spheroid.
SpheroidaL

SFHE'BOID is a species of ellipsoid (q.v.), and is represented by the same equation.
If an ellipse be made to revolve rouud one of its axes, the curved outline of the ellipse
describes the spheroid. Should the major or longer axis be the axis of revolution, the
spheroid is said to be prolate (Lat. prolatus, lengthened), but if the minor or shorter axis,
oblate. The earth's axis of revolution, which runs from pole to pole, being about 25 m.
shorter than the longest or equatorial diameter, and these being at right angles to each
other, the earth is considered as an oblate spheroid.

SPHEROID'AL CONDITION of liquids is the name usually given to a series of very;
singular phenomena discovered by Leidenfrost, but first carefully investigated by Bou-
tigny. Indeed, one, at least, of these phenomena has been popularly known for a very
long time, being the foundation of the rough practical method of determining whether
or not a flat-iron is so hot as to be likely to singe the linen to which it is to be applied.
The test consists simply in letting a drop of Tvater fall upon the iron ; if it be not too hot,
the drop spreads over the surface and evaporates. If it be too hot, the drop at once
glances off the iron without wetting it.

The common experimental method of exhibiting the spheroidal condition is easily
performed thus: A metallic disk, slightly concave, like a watch-case, is heated by a
lamp, and water is cautiously dropped on it from a pipette. If this be done before the
disk is sufficiently heated, the water boils almost explosively, and is dispersed at once in
vapor. But when the disk is hot enough, the water remains suspended above the sur
face; and the drop, when small, takes nearly the form of an oblate spheroid. Various
proofs have been given, though they are obviously unnecessary, that there is no contact
in this case. Thus, if the disk be very nearly flat, light passes freely between it and the
drop. Again, if one pole of a galvanic battery be connected with the disk, and the other
be dipped into the drop, a galvanometer interposed in the circuit shows that no current
passes. By heating the disk sufficiently, and dropping on the water very carefully, we
may easily keep in the spheroidal state as much water as, if not more than, it could hold
when cold. The explanation of the phenomenon is not yet quite clear; but there is no
doubt that the radiant heat from the disk raises vapor so freely from the surface of the drop
nearest it, as to interpose a cushion of dense and highly heated vapor between them, on
which the drop.as it were, floats ; the pressure of the vapor balancing its weight. This is not,
however, a quite complete explanation of the experiment, and it would require too much
detail to examine it more closely. But the most curious fact connected with the experi-
ment is, that the water does not boil. In fact, it evaporates so freely that the heat car-
ried off from it, as latent heat, by the vapor which is constantly formed, keeps its tem-
perature somewhere about 206 F. only. This suggests a curious experiment, which is
found to succeed. Boiling water, dropped on a red-hot plate of metal, instantly assumes
the spheroidal state, and is cooled six degrees below boiling.

It is not necessary that a metal plate be used a watch-glass will suffice for the
experiment; but hot water must be dropped on it, else the glass will crack.

Other liquids, and even some bodies which are solid at ordinary temperatures, can
be easily brought into the spheroidal state the lowest requisite temperature of the disk
being dependent on the boiling point of the substance. "Thus, while water has a tem-
perature of 206 F. in the spheroidal state, the disk must have a temperature of 340 F.
at least. For alcohol, these temperatures are 168 F. and 270 F. ; for ether, 94 F. and
140 F. A good example of a solid entering this state is furnished by dropping crystals
of iodine on a hot platinum disk.

It is not necessary that the disk should be solid ; it is easy to obtain ether, and even
water, in the spheroidal state over the surface of hot oil but great care is required, as
explosions are apt to occur, in which case the hot oil is freely thrown about.

Many cases of bursting of steam-boilers, otherwise apparently inexplicable, seem to
be attributable to this condition of matter. Thus, if we suppose that the water-supply
has run low, and the boiler has been overheated, it is conceivable that the contents may
sometimes be in the spheroidal state. The addition of cold water in such a case would
bring them suddenly in contact with the overheated metal, and large quantities of steam
would be generated with violence.

A very singular experiment, the freezing of water on a red-hot plate, is easily per-
formed by the help of this property of matter. Liquid sulphurous acid is so volatile as to
have a temperature of 13 Fahr. only, when in the spheroidal condition. As this is 19"
under the freezing-point of water, if a little water be dropped into the spheroid of acid,
it is at once frozen, and the pellet of ice can be dropped on the hand from the still red-
hot plate.

Even mercury can be frozen by a similar process, but as much greater cold ia
required, the substance in the spheroidal state is a mixture of solid carbonic acid and



The hand may be dipped for a short time with impunity into melted lead, and even
into melted copper. The vapor, instantly raised from the moisture of the skin, prevents,
*o long as that moisture lasts, more than an endurable amount of radiant boat from
reaching the hand, and also prevents direct contact. It is probable that a knowledge of
some forms of this phenomenon, in old days, was employed by priestcraft for the pur-
pose of protecting, when it was desirable to do so, the victims of the ordeal (q.v.) by fire.



Sphincter. f? 1 A

Bpices.

The phenomenon may easily be reversed. Thus, a red-hot silver ball, dropped into a
a vessel of water, is seen to glow for some time, till it has so far cooled that the
water comes into contact with it, when we have, as in the other form of the experiment,
an immediate and violent formation of vapor. The success of this experiment is greatly
aided by the addition of some strong ammonia to the water.

SPHINCTER MUSCLES (Gr. spMnktef, that which binds tight) are circular bands of
muscular fibers, whose function is to antagonize the expellent action of certain viscera,
especially the bladder and the lower part of the intestinal canal. It is to the presence of
these muscles that the higher animals owe the power of retaining for a considerable period
the excrementitious matters collected in the bladder and rectum, and of discharging
them at intervals, the sphincter muscles, being like those engaged in the process of
respiration, mainly, but not entirely, under the control of the will. Under certain con-
ditions, however, the necessity fur expelling the contents of these viscera becomes so
urgent that the sphincters lose their ordinary voluntary power.

SPHINX, a Greek word, signifying the squeezer or strangler, applied to certain
symbolical forms of Egyptian origin, having the body of a lion, a human or an ani-
mal head, and two wings attached to the sides. Various other combinations of
animal forms have been called by this name, although they are rather griffins or
chimeras. Human-headed sphinxes have been called androsphinxes; one with the head of
a ram, a criosphinx; with a hawk's head, a hieracosphinx. The form, when complete,
had wings added at the sides; but these are of a later period, and seem to have originated
with the Babylonians or Assyrians. In the Egyptian hieroglyphs, the sphinx bears the
name of Neb, or lord, and Akar, or intelligence, corresponding to the account of Clemens,
that these emblematic figures depicted intellect and force. The idea that they alle-
gorized the overflow of the Nile when The sun was in the constellations Leo and Virgo
appears quite unfounded. In Egypt the sphinx also appears as the symbolical form of
the monarch considered as a conqueror, the head of the reigning king being placed
upon a lion's body, the face bearded, and the usual dress-drapery being suspended
before it. Thus used, the sphinx was generally male; bat in the case of female rulers,
the figure has a female head and the body of a lioness.

The most remarkable sphinx is the Great Sphinx at Gizeh, a colossal form, hewn
out of the natural rock, and lying 300 ft. e. of the second pyramid. It is sculptured out
of a spur of the rock itself, to which masonry has been added in certain places, to com
plete the form, and measures 172 ft. 6 in. long by 56 ft. high. Immediately in front o'
the breast, Caviglia found, in 1816, a small naos, or chapel, formed of three hieroglyph-
ical tablets, dedicated by the monarchs Thothmss III. and Ramesses II. to the sphinx,
whom they adore under the name of Heremakhu, or Harmachis, as the Greek inscrip-
tions found at the same place call it i.e., the sun on the horizon. These tablets formed
three walls of the chapel; the fourth, in front, had a door in the center, and two couchant
lions placed upon it. A small lion was found on the pavement, 'and an altar between its
fore-paws, apparently for sacrifices offered to it in the time of the Romans. Before the
altar was a paved esplanade or dromos, leading to a staircase of thirty steps placed
between two walls, and repaired in the reigns of M. Aureliusand L.Verus, May 10, 166
A.D. In the reign of Severus and his sous, 199-200 A.D., another dromos in the same
line as the first, and a diverging staircase, were made, while some additions were
found to have been made to the parts between the two staircases in the reign of Nero.
Votive inscriptions of the Roman period, some as late as the 8;i c., were discovered
in the walls and constructions. On the second digit of the left claw of the sphinx, an
inscription, in pentameter Greek verses, by Arrian, probably of the time of Severus, was
discovered. Another metrical and prosaic inscription was also found. In addition to
these walls of unburnt brick, galleries and shafts were found in the rear of the sphinx,
extending northward. The excavations, however, of M. Mariette. in 1852, have thrown
further light on the sphinx, discovering the periholos, or outer wall that encircled it;
that the head only was sculptured, and that the sand which had accumulated round it was
brought by the hands of man, and not an encroachment of the desert; also that the
masonry of the belly was supported by a kind of abutment. To the s. of the sphinx,
Mariette found a dromos, which led to a temple built at the time of the 4th dynasty, of
huge blocks of alabaster and red granite. In the midst of the great chamber of thifl
temple were found seven statues, five mutilated and two entire, of the monarch Shaf-ra
or Cephren, made of a porphyritie granite. They are fine examples of ancient Egyptian
art. While the beauty and grandeur of the Great Sphinx have often attracted the admira
tion of travelers, its age has always remained a subject of doubt, but these later dis
coveries prove it to have been a monument of the age of the 4th dynasty, or contem-
porary with the pyramids.

Besides the great Sphinx, avenues of Sphinxes have been discovered at Saqqarah,
forming a dromos to the Serapeium of Memphis, and another dromos of the same at
the "Wady Esseboua. A Sphinx of the age of the shepherd dynasty has been found at
Tamils, and another of the same age is in the Louvre; and a granite Sphinx, found behind
the vocal Memnon, and inscribed with the name of Amenophis III., is at St. Petersburg.
An avenue of criosphiuxos has been found at Karnak. These are each about 17 ft. long,



* I 1 Sphincter.

' A L Spices.

and of the age of Horus, one of the last monarchs of tlie 18th dynasty. Various small
Sphinxes are in the different collections of Europe, but none of any very great antiquity.

The Theban Sphinx, whose myth first appears in Hcsiod, is described as having a
lion's body, female head, bird's wings, and serpent's tail, ideas probably derived from.
Phenician sources, which had adopted this symbolical form into the mythology from
Egypt. She was said to be the issue of Orthos, the two-headed dog of Geryon, by Chi-
maira, or of Typlion and Echidna, and was sent into the vicinity of Thebes" by Juno, to
punish the transgression of Laius, or, according to other accounts, by Bacchus, Mars, or
Pluto. See OEi)irus. The Sphinx was a favorite subject of ancient art, and appears in
bas-reliefs, on medals of Chios and other towns, and often as the decorations of arms
and furniture. In Assyria and Babylonia, representations of Sphinxes have been found,
and the same are not uncommon on Phenician works of art.

Birch, Mti#. of Classic Antiquit., ii. p. 27; Quart. Rev. xix. p. 412; Vyse, Pyramids,
iii. p. 107; Young, Hieroglyphicks, PI. 80; Letronne, Inscr., Grecq. ii. p. 460; Rev. Arch.,
1853, p. 715; 1860, p. 20; Schol. Euripid., i. 1, 1134; Hesiod, Tlieog., 326; Creuzer, Sym-
tolik, i. 495; Milliu, Gal. Myth., 502, 505.

SPHINX. See HAWK-MOTH.

SPHYGMOGRAPH, an instrument by which we ascertain, and permanently record, the
form, force, and frequency of the pulse-beat, and the changes which that beat undergoes
in certain morbid states. This instrument consists of two essential parts: (1) Of two
levers, one of which is so delicately adjusted on the vessel the pulsation of which it is
desired to examine, that on each expansion of the vessel the lever undergoes a correspond-
ing slight elevation: this lever communicates by a perpendicular arm with a second, to
which it transmits the impulse received from the vessel; the extremity of this second
lever is armed with a pen-point, which records the movements thus indicated on a mova-
ble plate, controlled by the second part of the instrument. (2) The second portion con-
sists of a plate, moved by watch-work, and bearing a strip of paper on which the sphyg-
inographic tracery is formed.

Mode in which (fa Tracery is formed. As the pulse transmits through the levers a ver-
tical movement to the pen-point, and tbe plate, on which the tracery is formed, is moved
steadily across the pen-point, an undulating line is the result: the height of the elevations
indicating the strength of the pulse; and the number of the elevations delineated in the
time the pen takes to travel its frequency. The tracings produced by the pulse at the
wrist in forms of cardiac disease exhibit the manner in which the tracing is modified in
diseased states of the circulatory system. In the case of a patient suffering from an
incompetent state of the valves guarding the orifice of the norta, the great vessel con-
veying blood from the heart, the blood, when propelled into the aorta, distends it, and
communicates a pulse throughout the arterial system. When the vessel again contracts,
regurgitation takes place into the cavity of the heart, as the valves, which should prevent
thisregurgitation, and maintain the arterial tension, are unable to perform their function.
The pulse-beat is accordingly abrupt, and of short duration, and the sphygmographic
tracing presents a series of abrupt elevations and depressions. In a different form
of cardiac disease, in which the valves are so affected as to obstruct the passage of
the blood into the circulation, the effect on the pulse is to render its beats weakly
marked and irregular; and in the sphygmographic tracing, the elevations are dimin-
ished in height and regularity. The pulse, in extreme forms of this lesion, is represented
in sphygmographic tracing by a slightly waving line.

SPHYR.E NID.S:, a family of fishes included by Cuvier in P, ro'dtr, but having the ven-
tral fins far behind the pectorals, and the bones of the pelvis quite detached from those
of the shoulder. The form is elongated; there are two dorsal fins; the scales are small
and cycloid: the mouth very large, with strong sharp teeth. The species are found in
the Mediterranean and in tropical seas. Some'attain a large size, as the BARRACOUDA,
or Barracouda Pike (Sphyrana barracouda), an inhabitant of the tropical parts of the
Atlantic ocean, which is scarcely less formidable than the white shaik. It is, however,
held in considerable estimation as an article of food, but at some seasons of the year
becomes unwholesome. It is a beautiful fish, of a rich green color above, and white
beneath. The I'KCTXA (5. vulgarix} is also valued as an article of food, and its scales and
air-bladder yield a substance used for making artificial pearls.

SPICCA'TO (Ital. separated), a musical term, indicative, like Staccato (q.v.), of a dis-
tinct and detached mode of performance. Its usual application is to music for bowed
instruments, where it implies that each note is to have a bow distinct from that which
precedes or follows it.

SPICE ISLANDS. See MOLUCCAS.

SPICES (Lat. specie*, kinds: in later Latin, kinds of goods, or produce in general;
ami then, the most highly prized kind of goods, the aromatic productions of the easH.
aromatic and pungent vegetable substances, used as condiments and for flavoring food.
They are almost exclusively the productions of tropical countries. In ancient times,
and throughout the middle ages, all the spices known in Europe were brought from
the east; and Arabia was regarded as the laud of spices, but rather because they came



Spider.
Spike.

through it, or were brought by its merchants, than because they were produced in it. for
they were really derived from the further east. They owe their aroma aiid pungency
chiefly ;o essential oils which they contain. They are yielded by different parts of
plants; some, as pepper, cayenne pepper, pimento, nutmeg, mace, and vanilla being the
Iruit or particular parts of the fruit; while some, as ginger, are the root-stock; and
others, as cinnamon and cassia, are the bark. Tropicul America produces some of the
spices, beiug the native region of cayenne pepper, pimento, and vanilla; but the greater
number are from the East Indies.

SPIDER, Aranea, a Linnsean genus, now divided not only into man^ genera, but into
laany families, and constituting a section (araneida) of the class arachnula, and order
pulmonaria. The species are very numerous, and are found in all parts of the world,
but most abundantly in tropical countries, which also produce the largest species, some
of them capable of making very small birds, and noi merely insects, their prey (see
BIRD-CATCHING SPIDER). The cephalothorax, formed by the combination of the head
and thorax into one piece, is covered with a kind of horny buckler, generally of an oval
form; the abdomen is attached to it by a short stalk, and ; .s generally soft and tumid.
Each of the eight legs consists of seven joints, the last arrr-ed with two hooks, which are
commonly toothed like a comb. The frontal claws, commonly called mandibles which
dp not, however, correspond to the mandibles of insects, and move in an entirely
different direction, up and down are terminated by a sharp movable hook, which has
near its extremity a small slit for the emission of a venomour fluid secreted in a gland
of the previous joint. The maxilla are two in number, and between them is an organ
called the tongue, forming part of the external apparatus of the mouth. The maxilla;
are the basal joints of the palpi, which resemble very small legs, and are often terminated
in the females by a small hook, but in the males by complicated and curious append-
ages, characteristic of the different genera and species. Spiders have generally eight
eyes, the relative position of which varies remarkably in the different families and
genera. A few species have only six eyes, and a very small nunber have only two.
The upper surface of the abdomen generally exhibits a number of in-pressed spots, most
conspicuous in those kinds which have a smooth naked skin. The pulmonary orifices
are either two or four in number, and are situated near the base of tht abdomen. Near"
the anus are several spinnerets, small protuberances, pierced at the ext> - emity with 8k
multitude of minute orifices, from which threads of extreme tenuity are produced, ali
" these threads combining to form one thread of the web. The substance which exudes
from the spinnerets is glutinous, and immediately dries into thread on coining in contact
with the air. It is elaborated in reservoirs, which terminate in intestine-like tubes. All
spiders have spinnerets, and produce threads, although all do not use them for the same
purposes; for they differ very much in their habits: some employ their webs in order to
catch their insect prey, while others depend for the capture of their prey on their power*
of running and leaping; and some weave for themselves habitations in which they live,
while others select holes and crevices as their places of abode. Almost all spiders
envelop their eggs in silken cocoons, which some of them tear open -when the young are
hatched; they are attentive to their young, some carrying them for a time on their back,
whrle some carry the cocoons or egg-cases beneath their breast, and others carry them
attached to the extremity of the abdomen. Nearly 2,000 eggs have been found in a
single cocoon, and the young, when set free, may be seen swarming over the body of
the mother, so as almost to conceal her from view. The female spider is, in many of
the species, much larger than the male, and a very remarkable danger attends thf
amatory approaches of the latter, as, if they are not favorably received, he is not uncom-
monly killed and eaten on the spot. Spiders are very pugnacious, and in their combats
often sustain the loss of limbs; but, like crustaceans, they possess the power of repairing
this loss. Like them also, they change their skin frequently during their growth ; but
they undergo no proper transformation. There is much similarity of form among all
the multitude of kinds. Many of them exhibit very brilliant and beautiful colors,



Online LibraryFrancis LieberLibrary of universal knowledge. A reprint of the last (1880) Edinburgh and London edition of Chambers' encyclopaedia, with copious additions by American editors (Volume 13) → online text (page 164 of 203)