Page:The New International Encyclopædia 1st ed. v. 18.djvu/514

* SPHERE. 442 SPHINX. to zones, segments, and sectors, see ^Mensuba- TION.) A remarkable property of the sphere is that its surface is equal to the curved surface of the circumscribed cylinder and its volume is two- thirds of that of the cylinder, a property said to ePHEBICAL HECTORS. THE LEFT ONE A SPHERICAL CONK. have been discovered by Archimedes (q.v.). If a sphere and a double cone be inscribed in an equi- lateral cylinder, the sphere and the volume be- tween the cone and tlie cylinder are Cavalieri bodies. See Cavaliebi. SPHERICAL TRIGONOMETRY. See Teigonometey. SPHEROGRAPH. See Sailings. SPHEROID. See Ellipsoid. SPHEROIDAL STATE ( from spheroid, from Gk. (r<paipoet5ris, s-pluiiiociJi's. like a ball or sphere, from fftpaipa, spliftiru, ball, globe -|- elSos, eidos, form ). The phenomenon observed when a drop of water placed on a highly heated surface remains in its spherical shape and moves about over the surface, evaporating gradually, instead of vaporizing instantaneously. ■ The ex- periment to show this condition of a liquid is gen- erally performed by using a metallic disk heated by a lamp or Bunsen burner, on which one or more drops of water are carefully let fall. If the disk is sufficiently heated a layer of vapor will be formed between its surface and the drop, which is known as the 'Crookes's layer.' The liquid re- mains suspended on this vapor and the drop takes the form of an oblate spheroid, the tem- perature, however, never rising above the boiling point, being in the ca.se of water about 206° F. or 96.6° C, while the disk itself must have a temperature of at least 340° F. or 171° C. The explanation of this fact is that the latent heat carried off in the course of vaporization is suf- ficient to keep the temperature below the boiling point. The drop does not actually touch the disk, but is supported on a cushion of vapor, which is evaporating toward the hot plate so rapidly as by its reaction to keep the water from falling. This may be seen by looking at a flame through the intervening space, or by attempting to pass an electric current from the drop of water to the metal disk, using a galvanometer to detect its passage, there being no deflection of the needle unless the two substances are in actual contact. The liquid takes a spherical shape owing to capil- lary action. Other liquids and bodies that are solid at ordinary temperatures also show this phenomenon, and instead of a metallic surface, that of a hot liquid can also be used. A striking illustration of this same principle is the immer- sion of a hand in molten metal, or in liquid air, the thin layer of aqueous vapor preventing the passage of the heat or cold to the hand. Consult: Stewart, EJcmeniarij Treatise on Beat (6th ed., Oxford, 180.5) ; Barker. PTii/sics (New York, 18n.31 ; Daniel, Text-Book of the Principles of Physics (3d ed.. New York, 1894). SPHINCTER MUSCLE (Lat. sphincter, from Gk. (npiynTTip, spJiinkIn; that which binds tight, sphincter, from atplyyeLv, sphingein, to strangle; possibly connected with Arm. pirk, tight). A circular band of muscular fibres, 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 excrement itious matters collected in (lie 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, imder the control of the will. SPHINX (Lat., from Gk. a-4>lyi, sphinx, from (Tipiyyeiv, sphinyein, to strangle). A composite monster, famous in Greek mythology, having the head of a woman, the body of a lion, the wings of a bird, and the tail of a serpent. According to the legend, she proposed a riddle to the Thebans, slaying all who were unable to guess it, and when tEdipus finally solved her riddle, she threw herself over a cliff and perished. She is said to have been the daughter of Echidna and her son Orthrus, or of Chimtera and her brother Orthrus. The name sphinx was applied by the Greeks to a class of composite figures, familiar in Egj'ptian art, having the body of a lion and the head of a man or of some animal. A figure of this sort with a human head was called an androsphinx; one having a ram's head, a criosphinx; and one with a hawk's head, a hieracosphinx. Like the winged bulls and lions found in Assyria, the Egyptian sphinx was the guardian genius of the temple before which it stood. The avenues lead- ing to many Egv'ptian temples were guarded by long rows of sphinxes placed at intervals on either side. Primarily the sphinx represented an imaginarv human-headed animal, living in the desert, and believed to 'he a favorite incarnation assumed by the Sun-god Re, As a iiile, the face was modeled after that of the reigning Pharaoh, the son of Re and his representative upon earth, and therefore Egyptian sphinxes were almost in- variably male, tiiough they might also present the features of a reigning queen. Where the sphinx has the head of an animal, the head is that of the animal sacred to the god before whose temple the figure is placed. The most remarkable of all Egyptian sphinxes is the Great Sphinx of Ghizeh, lying about 300 feet east of the second pyramid. It is sculptured out of the native rock, to which masonry has been added in certain places to complete the form. The bod,v is roughly hewn out, but the head was originall.v executed with great care. The entire height of the monument, from the crown of the head to the pavement on which the fore legs rest, is about 66 feet. In length the figure measures 172. .5 feet; the fore legs are 50 feet long; and the head is 30 feet long b.v nearly 14 feet in breadth. The face was originally colored red, but the color- ing has almost entirel.v disappeared. In 1816 the front of the Sphinx was cleared of sand b.v Caviglia. who found close to the breast a shrine, or small temple, containing an inscription of Thothmes IV. and one of Barneses II. Both monarchs had cleared away the sand that had accimnilated about the monument. From the inscription of Thothmes TV. it is clear that the