SIXETHVLAMIXE. 



S1RIU8 AND PROCYON. 



[Bcturicr ], and i* committed to the incumbent by the patron eiprnssly 

 without cure of >uU, the cure either not <n^g or being entrusted 

 to vicar ; thU u the strictest sine-cure. 2. Certain cathedral offices, 

 namely, the canonries and prebends, and, according to some authori- 

 ties, the deanery. S. Where a pariah is deatitute, by some accident, 

 of pariahioners ; this last kind has been called depopulations, rather 

 than nine cures. 



Rectors of a pariah in which vicars were likewise established with 

 cure of souk hare often by degrees exempted themselves from their 

 -jv-l.^if*l functions, and so hare obtained nine-cures ; but this U 

 rather by abuse than legitimately. Sine-cures are exempt from the 

 statute of pluralities. 



SIXKTHYLAMINE. [THKISWAMISK.] 



S1NKA1.INK. (C H 1} NO,) This alkaloid is a derivative of Six.v- 

 It is best obtained by Dealing hydro-sulphocyanate of siimpine 

 with baryta water until precipitation of sinapate of baryta ceases ; then 

 taking out hydrosulphocyanio acid by the sulphate of copper and iron ; 

 again adding excess of baryta water, and lastly separating baryta by a 

 current of carbonic acid. From the solution of carbonate of sinkaline, 

 thus obtained, the other salts may be formed by double decomposition. 

 The alkaloid itself is produced by the action of oxide of silver on 

 hydrochlorate of sinkalme. 



Solution of sinkaline is very unstable. Evaporated in vacuo, a 

 crystalline mass of the alkaloid is obtained, soon becoming brown in 

 contact with air. CUoroplatinate of niuto/iae contains (C^H^NO,, 

 HC1. PtCL). 



s I N K I X ( ; FOND. [NATIONAL DEBT, col. 878.] 



SIOUX INDIANS. TNoRTH AJIEBICAN INDIANS.] 



SIPHON (<rlf*r), a tube or pipe by which a liquid can be decanted 

 from one vessel to another without inverting or disturbing the Teasel 

 from which the liquid is withdrawn. This machine was probably 

 invented in the second century B.C., by Hero of Alexandria, who, in the 

 ' Spiritalia,' or ' Pneumatics,' mentiona its employment for the purpose 

 of conveying water from une valley to another over the intervening 

 ground. 



The siphon is a bent tube the arms of which are of unequal length : 

 one of the 'arms being immersed in the liquid which is to be drawn 

 from a vessel or reservoir, and the air being removed by auction, or by 

 means of a syringe, or by previously filling the siphon, the liquid in 

 the ronscl immediately rises in the immersed arm, in consequence of 

 the pressure of the atmosphere on that which surrounds the tube ; 

 then passing over the bend, it flows from the open orifice at the lower 

 extremity of the other arm. When the fluid to be raised is water, the 

 vertical height of the bend in the tube, above the surface of the water 

 in the vessel, must not exceed about 33 feet, because a column of 

 water of thai height would be in equilibrium with the pressure of the 

 atmosphere, and could not by the latter be forced over the bend. If 

 mercury were to be raised, the height of the bend in the siphon must, 

 for a similar reason, be less than 30 inches. The external arm of the 

 siphon must be longer than that which is immersed in the fluid, or its 

 orifice must be on a lower level than the surface of that fluid, in order 

 that the weight of the column of fluid in the former may exceed that 

 in the latter, and thus a continual stream be produced. 



The siphon is sometimes furnished with a suction or exhausting pipe 

 at the side, by means of which the air can be conveniently removed 

 anil the liquid be made to rise over the bend into the longer limb. 

 In the tt'urtrmbrrg tiphon the two ends are turned up, so that when 

 once filled it will always remain so, and act at once when one end is 

 immersed into a liquid. 



A siphon may be made to discharge water at the upper extremity by 

 means of an air-vessel at that place. Thus, while the tube is filled 

 with water, if the communication between the descending branch aud 

 the lower part of the air-vessel be closed by the shutting of a valve, 

 the water, which would have otherwise descended, rises in the vessel, 

 where it condenses the air ; and, from the reaction of the latter, it is 

 made to escape, as in a forcing-pump, through an open pipe whose 

 lower extremity is under the surface of the water in the vessel. This 

 was the invention of M. Hachette, and is denominated the ram tip/urn. 



I ii i .1 . I.T that a fluid may issue from that branch of a siphon which is 

 t Hi the exterior surface of the vessel containing it, it is necessary, as has 

 been stated above, that the extremity of the branch should be below the 

 level of the surface of the fluid in the vessel ; but it may be observed 

 that there is an exception to the rule when the interior diameter of 

 that branch is very small ; for example, when it is less than 1-1 Oth of 

 an inch, the interior diameter of the branch in the vessel being con- 

 siderably greater. For if such a fluid as water or wine be introduced 

 into a bent tube having one branch only very small, and the open ends 

 be uppermost, the top of the fluid in the more slender branch will, by 

 the effect of capillary attraction, stand higher than the top of that in 

 the other branch. It would follow therefore, that if the bent tube 

 were inverted, and the orifice of its larger branch were placed under 

 the surface of the fluid in a vessel, the fluid would begin to issue from 

 the other branch, though the orifice of the latter were a little above 

 the level of that surface. 



The effect of s siphon may be produced by capillary attraction 

 alone ; for if a piece of cotton cloth have one of its extremities in a 

 vessel of water, sod part of it be made to hang over the edge of the 

 I, the water will be attracted along the threads of the cloth, and 



will descend from thence in drops, provided the extremity of the 

 part thus hanging over be below the surface of the water in the vessel. 



The phenomena presented by springs of water are explain"! l.y 

 supposing that the rain which is absorbed in the earth occasionally 

 finds iu way by small channels to some interior cavity, and from thence 

 by other channels, which may be considered as natural siphons, to an 

 orifioe on a lower level at the surface of the ground. At this orifice it 

 issues in a stream of water, which continues to flow till the surface of 

 the water in the cavity has descended below the tojis of the vertical 

 bends in the channels : the water then ceases to flow till the rains 

 again raise the water in the cavity above those bends. But it some- 

 times happens that a spring, without ceasing to flow, discharges 

 |K-ri.Klically greater aud smaller quantities of water in given times ; 

 and this is accounted for by supposing the existence of two cavities 

 either unconnected or communicating with one another by small 

 channels. The channels leading from one of these cavities to the {mint 

 of efflux are supposed to be below the level of the water in both 

 cavities, so that the water flows through them continually ; but if the 

 channels from the other have vertical bends, so that they act as 

 siphons, aud at the same time these channels carry off the w.ii. r in 

 them faster than it can flow from the first cavity to the second, it will 

 be only when the water in the latter cavity is above the level of all 

 such bends that a discharge will take place from thence. As the water 

 in that cavity may only attain the necessary height in consequence of 

 periodical falls of rain, it will follow that corresponding increases in the 

 total quantity of water discharged can only then take place. 



For the amusement of young persons, several philosophical toys have 

 been constructed, in which the effects are produced by means of con- 

 pealed siphons. The siphon is sometimes placed within a figure in the 

 middle or on the edge of a cup, and sometimes between its exterior 

 and interior sides. Such are Tantalus' i Cup and the Siphon Pan 



SIPHON GAUGE, in pneumatics, is a tube of glass bent so as to 

 form two branches equal and parallel to one another, and each from 6 

 to 8 inches in length ; the tube is hermetically closed at one end and 

 left open at the other. One of the branches is filled with mercury ; 

 and, both of them being in vertical positions, with the closed and open 

 ends upwards, they are, by means of a brass stem terminating in a 

 screw, affixed generally to the under surface of the table carrying the 

 plate of an air-pump. The siphon is contained in a cylindrical glass 

 vessel, a little exceeding it in length, which is closed at the lower :.tni 

 open at the upper extremity ; and the open end of the cylinder is 

 screwed to the table of the air-pump immediately about the orifice of a 

 brass tube which passes through the pump-plate 'and opens into the 

 receiver placed upon the plate, so that there is a free communication 

 between the air in the cylinder, in the open leg of the siphon, and in 

 the receiver. This gauge has a scale of inches, decimally subdivided. 

 While the pressure of the air in the receiver and in the open branch of 

 the gauge is more than a counterbalance to the weight of the column 

 of mercury in the closed branch, the gauge presents no indications : 

 from the time however that, by continuing the process of exhausting 

 the receiver, the pressure of the air in the open branch becomes lass 

 than the weight of the column of mercury in the other, that column 

 descends in the latter branch and rises in the former ; and then the 

 degree of rarefaction in the receiver is indicated by the difference 

 between the heights of the columns of mercury in the two branches of 

 the siphon. [AIR-POMP; PEAB-GAUOE.] 



8IHEN8 (Sftprjvfs) are described iu the 'Odyssey' as two maiden > 

 who sat by the sea and BO charmed with their music all who sailed by, 

 that they remained on the spot till they died. Ulysses, by the direc- 

 tion of Circe, had himself tied to the mast, and stopped the ears of his 

 companions with wax, by which means he was able to hear their music, 

 and escape from its influence. (' Od.' xii. 39, Ac., 169.) The ship of 

 Ulysses, with himself tied to the mast, is frequently represent 

 gems, and other works of ancient art. The number of the Sirens was 

 afterwards increased to three, who are variously named l>y dillercnt 

 writers, Parthenope, Ligeia, and Leucosia; or Aglaope, PeisinoS, and 

 Thelxiepia. They were usually called the daughters of Mel|i< 

 and Achelous (Apollod., i. 3, 4), and were represented by artist* with 

 the feathers and wings of birds. (Compare Ovid, ' Met.,' v. 522, &c.) 

 According to the Liter writers they were urged by Hera to contend with 

 the Muses, who conquered them, and tore off their wings. (Pans., ix. 

 34, 2.) 



SIKIUS and PROCYON (2/pios and fyomW), the Greek names of 

 the bright stars in the constellations of the Great and Little Dog 

 [CAMS MAJUB and MINOR]. These are Orion's dogs, according to 

 some, and those of minor personages, according to others ; the whole 

 of their mythic explanations form a strong proof, in addition to those 

 already noticed, that the constellations are not Greek in then- origin. 

 The Egyptians called the dog-star Sothis [SoruiAO PERIOD], and from 

 IACAL rising had warning that the overflow of the Nile was 

 about to commence. Now the overflow of the Nile follows the 

 summer solstice ; whereas, by the precession of the equinoxes, the 

 heliacal rising of Sirius is now about the tenth of August. This 

 heliacal rising is a very indefinite phenomenon, and will serve any 

 system : by it Bailly, from Bainbridge's calculations, was able to carry 

 back the settlement of Egypt 2800 years before Christ : while Newton, 

 by a reckoning made on the same principles, made many ancient 

 events seem later than was generally supposed. 



