8PE 



673 



8PH 



and which reproduce themselves, by ge- 

 neration, in such a manner that we may 

 from analogy suppose them all sprung 

 originally from one single individual. 



SI>ECII>'IC. 1. A medicine possessed of 

 sovereign efficacy in the cure of a parti- 

 cular disease. 2. An epithet applied to 



a medicine which acts on some particular 

 organ more than on others. 



SPECIF'IC GHAV'ITY. The relative 

 weight of equal portions (as to hulk) of 

 different kinds of matter. See GRAVITT. 



SPECIT'IC NAME; is now used for the 

 name which, appended to the name of 

 the genus, constitutes the distinctive 

 name of the species. 



SPEC'TRES. A family of orthopterous 

 insects, comprehending such as have an 

 attenuated body. 



SPEC'TRCM, Lat. plural spectra, from 

 specto, to behold. 1. A visible form ; an 



image. 2. The image formed on any 



white surface by a ray of solar light 

 passing through a small hole into a dark 

 chamber, when refracted by a triangular 

 glass prism. The ray is divided into 

 seven, exhibiting the seven colours ob- 

 servable in the rainbow ; the image is 

 called the spectmm, and, because it is 

 produced by means of a prism, it is fur- 

 ther termed the prismatic spectrum, and 

 the colours making up the spectrum are 

 the prismatic^ colours (q. v.). 3. An ocu- 

 lar spectrum is an image of a bright ob- 

 ject, such as the setting sun, which con- 

 tinues for some time visible after closing 

 and covering the eyes. 



SPECCLTJM, Lat. from specio, to view. 



1. A mirror. 2. A metallic reflector, 



made use of in catadioptric telescopes, 

 instead of the object-glass used in the 

 dioptric telescopes. The speculum metal 

 is an alloy of copper and tin. 3. A sur- 

 gical instrument for opening or obtain- 

 ing a view of parts. 



SI-EISS, (A compound ore of nickel and 



SPEISE. ant-miry 



SPELT. A name ?ft that species of Tri- 

 ticum called otherwise German wheat. 



SPEL'TER. The commercial name of 

 zinc Jq. v.). 



SPERMACE'TI, from a-ri^/Mx,, seed, and 

 xr,ros, the whale. A product obtained 

 from the brain of the Physeter macroce- 

 phalus, or long-headed whale, which in- 

 habits the southern ocean. The brain 

 being dug out of the cavity of the head, 

 and the oil separated from it by dripping, 

 the residue is crude spermaceti, which is 

 purified and used in the manufacture of 

 candles, in medicine, &c. 



SPERMOPH'ILUS. The generic name 

 given by Fred. Cuvier to those marmots 

 that have cheek pouches. The superior 

 lightness of their structure has caused 

 them to be called ground squirrelt. East- 



ern Europe produces one species, the 

 souslik or zizel ; America produces several 

 of them. 



SPHA'CEL, from trfctxu, to destroy ; com- 

 plete mortification. 



SPHACEI/ISM, from trtfotxo^u, to gan- 

 grene. 1. A gangrene. 2. An inflam- 

 mation of the brain. 



SFHAG'NOUS. Mossy; containing peat- 

 moss. 



SPHAG'NUM PALUS'TRE. A kind of moss, 

 the decayed roots of which constitute the 

 greater part of peat-moss. 



SPHENE, from f^v, a wedge. A min- 

 eral, a silicate of titanium and lime. Its 

 colours are commonly greyish, yellowish, 

 reddish, and blackish brown, with various 

 shades of green. It is found amorphous 

 and in crystals. 



SPHENO'ID, from <r$'/iv, a wedge, and 

 u$o; , likeness. "Wedge-like : applied to a 

 bone of the skull (sphenoides os], because 

 it-is wedged in among the other bones of 

 the head. 



SPHE'NO-MAX'IT-LARY. Relating to the 

 sphenoid and maxillary bones. 



SPHE'NO-PAI/ATINE. Relating to the 

 sphenoid and palate bones. 



SPHE^NO-PARI'ETAL. Relating to the 

 sphenoid and parietal bones. 



SPBE'NO-TEM'PORAL. Relating to the 

 sphenoid and temporal bones. 



SPHERE, Lat. sphara, Gr. rQeutot- -A- 

 globe : a solid generated by the revolution 

 of a semicircle about its diameter, which 

 remains fixed. The centre of a sphere is 

 equidistant from every point of its sur- 

 face, and all its radii are equal. 



SPHE'RICAL EXCESS is the sum by which 

 the three angles of a triangle, on the r.r- 

 face of a sphere or spheroid, exceeds .wo 

 right angles. 



SPHE'RICS. The doctrine of the sphere 

 and spheroid. The solid contents of a 

 sphere or spheroid is found by multiply- 

 ing the square of the equatorial diameter 

 by the axis of rotation and the product 

 by 5236. 



SPHE'ROID, from trpetigai, a sphere, and 

 lidos, like. A solid approaching the figure , 

 of a sphere, formed by the revolution of 

 a semi-ellipsis about its axis. When it is 

 generated by the revolution of a semi- 

 i-llipsis about its transverse or longest 

 diameter, it is an oblong spheroid ; when 

 about its conjugate or shortest diameter, 

 it is a prolate spheroid. The fixed axis of 

 the ellipse is called the axis of rotation ; 

 the circle described by the semi-axis of 

 the ellipse is the equatorial circle. 



SPHERO'METER, fQa,i<* and yucr;oy, 

 measure. An instrument for measuring 

 the thickness of small bodies, the curva- 

 ture of optical glasses, &c. 



SFHEX. The solitary or savage wasp : 



2 x 



